Wound based sensor system with ambient atmosphere monitoring

ABSTRACT

Systems, apparatuses, and methods for providing negative pressure and/or instillation fluids to a tissue site are disclosed. Some embodiments are illustrative of an apparatus or system for delivering negative-pressure and/or therapeutic solution of fluids to a tissue site, which can be used in conjunction with sensing properties of fluids extracted from a tissue site and/or instilled at a tissue site. For example, an apparatus may comprise a dressing interface or connector that includes a pH sensor, a humidity sensor, a temperature sensor and/or a pressure sensor embodied on a single pad within the connector and proximate the tissue site to provide data indicative of acidity, humidity, temperature and pressure. Such apparatus may further comprise an ambient port for providing the pressure sensor and the humidity sensor with access to the ambient environment providing readings relative to the atmospheric pressure and humidity.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/785,026, entitled “Wound Based Sensor System withAmbient Atmosphere Monitoring,” filed Dec. 26, 2018, which isincorporated herein by reference for all purposes.

TECHNICAL FIELD

The invention set forth in the appended claims relates generally totissue treatment systems and more particularly, but without limitation,to systems and methods for providing negative-pressure therapy withinstillation of topical treatment solutions requiring access to theambient environment.

BACKGROUND

Clinical studies and practice have shown that reducing pressure inproximity to a tissue site can augment and accelerate growth of newtissue at the tissue site. The applications of this phenomenon arenumerous, but it has proven particularly advantageous for treatingwounds. Regardless of the etiology of a wound, whether trauma, surgery,or another cause, proper care of the wound is important to the outcome.Treatment of wounds or other tissue with reduced pressure may becommonly referred to as “negative-pressure therapy,” but is also knownby other names, including “negative-pressure wound therapy,”“reduced-pressure therapy,” “vacuum therapy,” “vacuum-assisted closure,”and “topical negative-pressure,” for example. Negative-pressure therapymay provide a number of benefits, including migration of epithelial andsubcutaneous tissues, improved blood flow, and micro-deformation oftissue at a wound site. Together, these benefits can increasedevelopment of granulation tissue and reduce healing times.

There is also widespread acceptance that cleansing a tissue site can behighly beneficial for new tissue growth. For example, a wound can bewashed out with a stream of liquid solution, or a cavity can be washedout using a liquid solution for therapeutic purposes. These practicesare commonly referred to as “irrigation” and “lavage” respectively.“Instillation” is another practice that generally refers to a process ofslowly introducing fluid to a tissue site and leaving the fluid for aprescribed period of time before removing the fluid. For example,instillation of topical treatment solutions over a wound bed can becombined with negative-pressure therapy to further promote wound healingby loosening soluble contaminants in a wound bed and removing infectiousmaterial. As a result, soluble bacterial burden can be decreased,contaminants removed, and the wound cleansed.

While the clinical benefits of negative-pressure therapy andinstillation therapy are widely known, improvements to therapy systems,components, and processes may benefit healthcare providers and patients.

BRIEF SUMMARY

New and useful systems, apparatuses, and methods for instilling fluid toa tissue site in a negative-pressure therapy environment are set forthin the appended claims. Illustrative embodiments are also provided toenable a person skilled in the art to make and use the claimed subjectmatter. Some embodiments are illustrative of an apparatus or system fordelivering negative-pressure and therapeutic solution of fluids to atissue site, which can be used in conjunction with sensing properties ofwound exudates extracted from a tissue site. For example, an apparatusmay include a pH sensor, a humidity sensor, a temperature sensor and apressure sensor embodied on a single pad proximate the tissue site toprovide data indicative of acidity, humidity, temperature and pressure.Such apparatus may further comprise an ambient port for providing thepressure sensor and the humidity sensor with access to the ambientenvironment providing readings relative to the atmospheric pressure andhumidity.

In some embodiments, for example, an apparatus may include a dressinginterface for connecting a source of fluids to a tissue interface andsensing properties of fluid at a tissue site. The dressing interface maycomprise a housing having a body including a therapy cavity and acomponent chamber fluidly isolated from the therapy cavity, wherein thetherapy cavity has an opening configured to be in fluid communicationwith the tissue interface. The dressing interface may further comprise anegative-pressure port fluidly coupled to the therapy cavity and adaptedto be fluidly coupled to a negative-pressure source, and also an ambientport fluidly coupled to the component chamber and adapted to be fluidlycoupled to an ambient environment. The dressing interface may furthercomprise a control device disposed within the component chamber andincluding a microprocessor. The dressing interface may further compriseat least one sensor electrically coupled to the microprocessor andhaving a sensing portion disposed within the therapy cavity and furtherhaving an ambient input fluidly coupled to the component chamber of thedressing interface.

In some embodiments, the at least one sensor may comprise at least oneof a pressure sensor, a temperature sensor, and a humidity sensor. Insome example embodiments, the dressing interface may further comprise afluid conduit having a first end coupled to the ambient port and asecond end, and further comprise a fluid connector having a connectorport fluidly coupled to the second end and the ambient environmentthrough an orifice in the fluid connector. In other example embodiments,the dressing interface may further comprise a fluid conduit having afirst end coupled to the ambient port and a second end, wherein thesecond end is configured to terminate proximate a canister fluidlycoupled to the therapy cavity and having an orifice configured to accessthe ambient environment. In yet other example embodiments, the dressinginterface may further comprise a fluid conduit having a first endcoupled to the ambient port and a second end, wherein the second end isconfigured to terminate within a canister fluidly coupled to the therapycavity and having an orifice configured to access the ambientenvironment.

In some embodiments, the dressing interface may further comprise a ventport fluidly coupled to the therapy cavity and adapted to enable airflowinto the therapy cavity. The dressing interface may further comprise aninstillation port fluidly coupled to the therapy cavity and adapted tofluidly couple an instillation source to the tissue interface. Thedressing interface may further comprise a first baffle disposedproximate the reduced-pressure port and a second baffle disposedproximate the installation port, both extending into the therapy cavityto direct the flow of fluids within the therapy cavity. The dressinginterface may further comprise a temperature sensor and a humiditysensor, each sensor having a sensing portion disposed within the therapycavity and electrically coupled to the microprocessor through the bodyof the housing. The sensing portion of the humidity sensor and thetemperature sensor may be disposed proximate the instillation port.

Some embodiments are illustrative of applying negative-pressure to atissue interface and sensing properties of fluid at a tissue site. Inone example embodiment, the method may comprise positioning a dressinginterface wherein the dressing interface comprises a housing having abody including a therapy cavity and a component chamber fluidly isolatedfrom the therapy cavity, wherein the therapy cavity has an openingconfigured to be in fluid communication with the tissue interface. Thedressing interface may further comprise a negative-pressure port fluidlycoupled to the therapy cavity, an ambient port fluidly coupled to thecomponent chamber, a control device disposed within the componentchamber, and at least one sensor having a sensing portion disposedwithin the therapy cavity and coupled to the control device. Thedressing interface may further comprise an ambient input fluidly coupledto the component chamber for providing the sensor access to the ambientenvironment. The method may further comprise applying negative pressureto the therapy cavity to draw fluids from the tissue interface and intothe therapy cavity. The method may further comprise sensing propertiesof the ambient environment provided by the at least one sensor throughthe ambient input and the component chamber, and sensing properties ofthe fluids within the therapy cavity provided by the at least one sensoras compared to the properties of the ambient environment.

Some embodiments are illustrative of a method for applying fluids to atissue interface and sensing a property of a fluid at a tissue site fortreating the tissue site. For example, the method may comprisepositioning a dressing interface on the tissue site, the dressinginterface having a housing having a body including a therapy cavity anda component chamber fluidly isolated from the therapy cavity, thetherapy cavity having an opening configured to be in fluid communicationwith the tissue interface, and a control device disposed within thecomponent chamber. The method may further comprise providing thecomponent chamber with access to the ambient environment through anambient port to a sensor disposed within the therapy cavity and coupledto the control device. The method also comprises applying negativepressure to the therapy cavity through a negative-pressure port to drawfluids from the tissue interface and into the therapy cavity. The methodmay also comprise sensing the property of the fluid within the therapycavity with the sensor, and then providing a property signal to thecontrol device indicative of the property of the fluid relative to thecorresponding property of the ambient environment.

Some other embodiments are illustrative of a method for applying fluidsto a tissue interface and sensing properties of fluids at a tissue sitefor treating the tissue site. For example, the method may comprisepositioning a dressing interface on the tissue site, wherein thedressing interface may have a housing including an outside surface and atherapy cavity having an opening configured to be in fluid communicationwith the tissue interface. The dressing interface may further comprise areduced-pressure port fluidly coupled to the therapy cavity and adaptedto fluidly couple a reduced-pressure source to the therapy cavity, aninstillation port fluidly coupled to the therapy cavity and adapted tofluidly couple an instillation source to the therapy cavity, and a pHsensor and a pressure sensor disposed within the therapy cavity and eachelectrically coupled to a control device. The method may furthercomprise applying reduced pressure to the therapy cavity to draw fluidsfrom the tissue interface and into the therapy cavity, and sensing pHand pressure properties of the fluids within the therapy cavity providedfrom the pressure sensor and the pH sensor. The method may furthercomprise instilling fluids into the therapy cavity to cleanse thepressure sensor and the pH sensor.

Objectives, advantages, and a preferred mode of making and using theclaimed subject matter may be understood best by reference to theaccompanying drawings in conjunction with the following detaileddescription of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of an example embodiment of atherapy system for providing negative-pressure including bothinstillation and venting capabilities in accordance with thisspecification;

FIG. 2A is a graph illustrating an illustrative embodiment of pressurecontrol modes for the negative-pressure and instillation therapy systemof FIG. 1 wherein the x-axis represents time in minutes (min) and/orseconds (sec) and the y-axis represents pressure generated by a pump inTorr (mmHg) that varies with time in a continuous pressure mode and anintermittent pressure mode that may be used for applying negativepressure in the therapy system;

FIG. 2B is a graph illustrating an illustrative embodiment of anotherpressure control mode for the negative-pressure and instillation therapysystem of FIG. 1 wherein the x-axis represents time in minutes (min)and/or seconds (sec) and the y-axis represents pressure generated by apump in Torr (mmHg) that varies with time in a dynamic pressure modethat may be used for applying negative pressure in the therapy system;

FIG. 3 is a flow chart showing an illustrative embodiment of a therapymethod for providing negative-pressure and instillation therapy fordelivering treatment solutions to a dressing at a tissue site;

FIG. 4 is a sectional side view of a first dressing interface comprisinga housing and a wall disposed within the housing and forming a therapycavity including sensors and a component cavity including electricaldevices that may be associated with some example embodiments of thetherapy system of FIG. 1 for providing negative pressure including bothinstillation and venting capabilities to the therapy cavity through asingle conduit;

FIG. 5A is a perspective top view of the first dressing interface ofFIG. 4 , FIG. 5B is a side view of the first dressing interface of FIG.4 disposed on a tissue site, and FIG. 5C is an end view of the firstdressing interface of FIG. 4 disposed on the tissue site;

FIG. 6A is an assembly view of the first dressing interface of FIG. 4comprising components of the housing and a first example embodiment of asensor assembly including the wall, the sensors, and the electricaldevices;

FIG. 6B is a system block diagram of the sensors and electrical devicescomprising the sensor assembly of FIG. 6A;

FIGS. 7A, 7B and 7C are a top view, side view, and bottom view,respectively, of the sensor assembly of FIG. 6 ;

FIG. 7D is a perspective top view of the sensor assembly of the sensorassembly of FIG. 6 including one example embodiment of a pH sensor;

FIG. 8A is a perspective bottom view of the first dressing interface ofFIG. 4 , and FIG. 8B is a bottom view of the first dressing interface ofFIG. 4 ;

FIG. 9A is a top view of a first embodiment of a pH sensor that may beused with the sensor assembly of FIG. 8D, and FIG. 9B is a top view of asecond embodiment of a pH sensor that may be used with the sensorassembly of FIG. 8D;

FIG. 10A is a sectional side view of a second dressing interfacecomprising a housing and a wall disposed within the housing and forminga therapy cavity including sensors and a component cavity includingelectrical devices that may be associated with some example embodimentsof the therapy system of FIG. 1 for providing negative pressureincluding instillation to the therapy cavity through separate ports;

FIG. 10B is a sectional bottom view of the second dressing interface ofFIG. 10A taken along the line 10B-10B showing the sensors and bafflesdisposed within the therapy cavity;

FIG. 11A is a sectional side view of a third dressing interface which isa modified version of the second dressing interface of FIGS. 10A and 10Bfurther comprising a third port for venting to the therapy cavity;

FIG. 11B is a sectional bottom view of a third dressing interface ofFIG. 11A taken along the line 11B-11B showing the sensors and bafflesdisposed within the therapy cavity;

FIG. 12 is a schematic diagram of a fluid conduit including an in-lineconnector that may be associated with some example embodiments of thedressing interfaces of FIGS. 1, 4, 10A and 11A for providing negativepressure and/or instillation including access to the ambient environmentprovided to a component chamber of the dressing interfaces;

FIG. 13A is a cross-sectional, schematic view of a first embodiment ofthe fluid conduit of FIG. 12 including a negative pressure lumen, a ventlumen, and an ambient lumen; and

FIG. 13B is a cross-sectional, schematic view of a second embodiment ofthe fluid conduit of FIG. 12 including a negative pressure lumen, andinstillation lumen, a vent lumen, and an ambient lumen.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The following description of example embodiments provides informationthat enables a person skilled in the art to make and use the subjectmatter set forth in the appended claims, but may omit certain detailsalready well-known in the art. The following detailed description is,therefore, to be taken as illustrative and not limiting.

The example embodiments may also be described herein with reference tospatial relationships between various elements or to the spatialorientation of various elements depicted in the attached drawings. Ingeneral, such relationships or orientation assume a frame of referenceconsistent with or relative to a patient in a position to receivetreatment. However, as should be recognized by those skilled in the art,this frame of reference is merely a descriptive expedient rather than astrict prescription.

The term “tissue site” in this context broadly refers to a wound,defect, or other treatment target located on or within tissue, includingbut not limited to, bone tissue, adipose tissue, muscle tissue, neuraltissue, dermal tissue, vascular tissue, connective tissue, cartilage,tendons, or ligaments. A wound may include chronic, acute, traumatic,subacute, and dehisced wounds, partial-thickness burns, ulcers (such asdiabetic, pressure, or venous insufficiency ulcers), flaps, and grafts,for example. The term “tissue site” may also refer to areas of anytissue that are not necessarily wounded or defective, but are insteadareas in which it may be desirable to add or promote the growth ofadditional tissue. For example, negative pressure may be applied to atissue site to grow additional tissue that may be harvested andtransplanted.

The present technology also provides negative pressure therapy devicesand systems, and methods of treatment using such systems withantimicrobial solutions. FIG. 1 is a simplified functional block diagramof an example embodiment of a therapy system 100 that can providenegative-pressure therapy with instillation of treatment solutions inaccordance with this specification. The therapy system 100 may include anegative-pressure supply, and may include or be configured to be coupledto a distribution component, such as a dressing. In general, adistribution component may refer to any complementary or ancillarycomponent configured to be fluidly coupled to a negative-pressure supplybetween a negative-pressure supply and a tissue site. A distributioncomponent is preferably detachable, and may be disposable, reusable, orrecyclable. For example, a dressing 102 is illustrative of adistribution component that may be coupled to a negative-pressure sourceand other components. The therapy system 100 may be packaged as asingle, integrated unit such as a therapy system including all of thecomponents shown in FIG. 1 that are fluidly coupled to the dressing 102.The therapy system may be, for example, a V.A.C. Ulta™ System availablefrom Kinetic Concepts, Inc. of San Antonio, Tex.

The dressing 102 may be fluidly coupled to a negative-pressure source104. A dressing may include a cover, a tissue interface, or both in someembodiments. The dressing 102, for example, may include a cover 106, adressing interface 107, and a tissue interface 108. A computer or acontroller device, such as a controller 110, may also be coupled to thenegative-pressure source 104. In some embodiments, the cover 106 may beconfigured to cover the tissue interface 108 and the tissue site, andmay be adapted to seal the tissue interface and create a therapeuticenvironment proximate to a tissue site for maintaining a negativepressure at the tissue site. In some embodiments, the dressing interface107 may be configured to fluidly couple the negative-pressure source 104to the therapeutic environment of the dressing. The therapy system 100may optionally include a fluid container, such as a container 112,fluidly coupled to the dressing 102 and to the negative-pressure source104.

The therapy system 100 may also include a source of instillationsolution, such as a solution source 114. A distribution component may befluidly coupled to a fluid path between a solution source and a tissuesite in some embodiments. For example, an instillation pump 116 may becoupled to the solution source 114, as illustrated in the exampleembodiment of FIG. 1 . The instillation pump 116 may also be fluidlycoupled to the negative-pressure source 104 such as, for example, by afluid conductor 119. In some embodiments, the instillation pump 116 maybe directly coupled to the negative-pressure source 104, as illustratedin FIG. 1 , but may be indirectly coupled to the negative-pressuresource 104 through other distribution components in some embodiments.For example, in some embodiments, the instillation pump 116 may befluidly coupled to the negative-pressure source 104 through the dressing102. In some embodiments, the instillation pump 116 and thenegative-pressure source 104 may be fluidly coupled to two differentlocations on the tissue interface 108 by two different dressinginterfaces. For example, the negative-pressure source 104 may be fluidlycoupled to the dressing interface 107 while the instillation pump 116may be fluidly to the coupled to dressing interface 107 or a seconddressing interface 117. In some other embodiments, the instillation pump116 and the negative-pressure source 104 may be fluidly coupled to twodifferent tissue interfaces by two different dressing interfaces, onedressing interface for each tissue interface (not shown).

The therapy system 100 also may include sensors to measure operatingparameters and provide feedback signals to the controller 110 indicativeof the operating parameters properties of fluids extracted from a tissuesite. As illustrated in FIG. 1 , for example, the therapy system 100 mayinclude a pressure sensor 120, an electric sensor 124, or both, coupledto the controller 110. The pressure sensor 120 may be fluidly coupled orconfigured to be fluidly coupled to a distribution component such as,for example, the negative-pressure source 104 either directly orindirectly through the container 112. The pressure sensor 120 may beconfigured to measure pressure being generated by the negative-pressuresource 104, i.e., the pump pressure (PP). The electric sensor 124 alsomay be coupled to the negative-pressure source 104 to measure the pumppressure (PP). In some example embodiments, the electric sensor 124 maybe fluidly coupled proximate the output of the output of thenegative-pressure source 104 to directly measure the pump pressure (PP).In other example embodiments, the electric sensor 124 may beelectrically coupled to the negative-pressure source 104 to measure thechanges in the current in order to determine the pump pressure (PP).

Distribution components may be fluidly coupled to each other to providea distribution system for transferring fluids (i.e., liquid and/or gas).For example, a distribution system may include various combinations offluid conductors and fittings to facilitate fluid coupling. A fluidconductor generally includes any structure with one or more luminaadapted to convey a fluid between two ends, such as a tube, pipe, hose,or conduit. Typically, a fluid conductor is an elongated, cylindricalstructure with some flexibility, but the geometry and rigidity may vary.Some fluid conductors may be molded into or otherwise integrallycombined with other components. A fitting can be used to mechanicallyand fluidly couple components to each other. For example, a fitting maycomprise a projection and an aperture. The projection may be configuredto be inserted into a fluid conductor so that the aperture aligns with alumen of the fluid conductor. A valve is a type of fitting that can beused to control fluid flow. For example, a check valve can be used tosubstantially prevent return flow. A port is another example of afitting. A port may also have a projection, which may be threaded,flared, tapered, barbed, or otherwise configured to provide a fluid sealwhen coupled to a component.

In some embodiments, distribution components may also be coupled byvirtue of physical proximity, being integral to a single structure, orbeing formed from the same piece of material. Coupling may also includemechanical, thermal, electrical, or chemical coupling (such as achemical bond) in some contexts. For example, a tube may mechanicallyand fluidly couple the dressing 102 to the container 112 in someembodiments. In general, components of the therapy system 100 may becoupled directly or indirectly. For example, the negative-pressuresource 104 may be directly coupled to the controller 110, and may beindirectly coupled to the dressing interface 107 through the container112 by conduit 126 and conduit 135, also referred to herein as negativepressure conduit 126 and negative pressure conduit 135. The pressuresensor 120 may be fluidly coupled to the dressing 102 directly (notshown) or indirectly through the container 112 and a filter 122 byconduit 121 and conduit 155. The filter 122 may be any type of filterfor preventing the ingress of liquids from the container 112.Additionally, the instillation pump 116 may be coupled indirectly to thedressing interface 107 through the solution source 114 and aninstillation regulator 115 by fluid conductors 132 and 133, alsoreferred to herein as instillation conduit 133. The instillationregulator 115 may be electrically coupled to the controller 110 (notshown) that may be programmed along with the instillation pump 116 todeliver instillation fluid in a controlled fashion. Alternatively, theinstillation pump 116 may be coupled indirectly to the second dressinginterface 117 through the solution source 114 and the instillationregulator 115 by instillation conduits 133 and 134.

Some embodiments of the therapy system 100 may include a solutionsource, such as solution source 114, without an instillation pump, suchas the instillation pump 116. Instead, the solution source 114 may befluidly coupled directly or indirectly to the dressing interface 107 andmay further include the instillation regulator 115 electrically coupledto the controller 110 as described above. In operation, the negativepressure source 104 may apply negative pressure to the dressinginterface 107 through the container 112 and the negative pressureconduit 135 to create a vacuum within the spaces formed by the dressinginterface 107 and the tissue interface 108. The vacuum within the spaceswould draw instillation fluid into the spaces for cleansing or providingtherapy treatment to the tissue site. In some embodiments, thecontroller 110 may be programmed to modulate the instillation regulator115 to control the flow of instillation fluid into the spaces. Inanother example embodiment, the therapy system 100 may include both theinstillation pump 116 and the negative pressure source 104 toalternately deliver instillation fluid to the dressing interface 107 byproviding a positive pressure to the solution source 114 and a negativepressure directly to the dressing interface 107, respectively. Any ofthe embodiments described above may be utilized to periodically clean,rinse, or hydrate the tissue site using saline along with otherpH-modulating instillation fluids such as weak acidic acids.

The fluid mechanics of using a negative-pressure source to reducepressure in another component or location, such as within a sealedtherapeutic environment, can be mathematically complex. However, thebasic principles of fluid mechanics applicable to negative-pressuretherapy and instillation are generally well-known to those skilled inthe art, and the process of reducing pressure may be describedillustratively herein as “delivering,” “distributing,” or “generating”negative pressure, for example.

In general, exudates and other fluids flow toward lower pressure along afluid path. Thus, the term “downstream” typically implies something in afluid path relatively closer to a source of negative pressure or furtheraway from a source of positive pressure. Conversely, the term “upstream”implies something relatively further away from a source of negativepressure or closer to a source of positive pressure. Similarly, it maybe convenient to describe certain features in terms of fluid “inlet” or“outlet” in such a frame of reference. This orientation is generallypresumed for purposes of describing various features and componentsherein. However, the fluid path may also be reversed in someapplications (such as by substituting a positive-pressure source for anegative-pressure source) and this descriptive convention should not beconstrued as a limiting convention.

“Negative pressure” generally refers to a pressure less than a localambient pressure, such as the ambient pressure in a local environmentexternal to a sealed therapeutic environment provided by the dressing102. In many cases, the local ambient pressure may also be theatmospheric pressure at which a tissue site is located. Alternatively,the pressure may be less than a hydrostatic pressure associated withtissue at the tissue site. Unless otherwise indicated, values ofpressure stated herein are gauge pressures. Similarly, references toincreases in negative pressure typically refer to a decrease in absolutepressure, while decreases in negative pressure typically refer to anincrease in absolute pressure. While the amount and nature of negativepressure applied to a tissue site may vary according to therapeuticrequirements, the pressure is generally a low vacuum, also commonlyreferred to as a rough vacuum, between −5 mm Hg (−667 Pa) and −500 mm Hg(−66.7 kPa). Common therapeutic ranges are between −75 mm Hg (−9.9 kPa)and −300 mm Hg (−39.9 kPa).

A negative-pressure supply, such as the negative-pressure source 104,may be a reservoir of air at a negative pressure, or may be a manual orelectrically-powered device that can reduce the pressure in a sealedvolume, such as a vacuum pump, a suction pump, a wall suction portavailable at many healthcare facilities, or a micro-pump, for example. Anegative-pressure supply may be housed within or used in conjunctionwith other components, such as sensors, processing units, alarmindicators, memory, databases, software, display devices, or userinterfaces that further facilitate therapy. For example, in someembodiments, the negative-pressure source 104 may be combined with thecontroller 110 and other components into a therapy unit. Anegative-pressure supply may also have one or more supply portsconfigured to facilitate coupling and de-coupling the negative-pressuresupply to one or more distribution components.

The tissue interface 108 can be generally adapted to contact a tissuesite. The tissue interface 108 may be partially or fully in contact withthe tissue site. If the tissue site is a wound, for example, the tissueinterface 108 may partially or completely fill the wound, or may beplaced over the wound. The tissue interface 108 may take many forms, andmay have many sizes, shapes, or thicknesses depending on a variety offactors, such as the type of treatment being implemented or the natureand size of a tissue site. For example, the size and shape of the tissueinterface 108 may be adapted to the contours of deep and irregularshaped tissue sites. Moreover, any or all of the surfaces of the tissueinterface 108 may have projections or an uneven, course, or jaggedprofile that can induce strains and stresses on a tissue site, which canpromote granulation at the tissue site.

In some embodiments, the tissue interface 108 may be a manifold such asmanifold 408 shown in FIG. 4 . A “manifold” in this context generallyincludes any substance or structure providing a plurality of pathwaysadapted to collect or distribute fluid across a tissue site underpressure. For example, a manifold may be adapted to receive negativepressure from a source and distribute negative pressure through multipleapertures across a tissue site, which may have the effect of collectingfluid from across a tissue site and drawing the fluid toward the source.In some embodiments, the fluid path may be reversed or a secondary fluidpath may be provided to facilitate delivering fluid across a tissuesite.

In some illustrative embodiments, the pathways of a manifold may beinterconnected to improve distribution or collection of fluids across atissue site. In some illustrative embodiments, a manifold may be aporous foam material having interconnected cells or pores. For example,cellular foam, open-cell foam, reticulated foam, porous tissuecollections, and other porous material such as gauze or felted matgenerally include pores, edges, and/or walls adapted to forminterconnected fluid channels. Liquids, gels, and other foams may alsoinclude or be cured to include apertures and fluid pathways. In someembodiments, a manifold may additionally or alternatively compriseprojections that form interconnected fluid pathways. For example, amanifold may be molded to provide surface projections that defineinterconnected fluid pathways.

The average pore size of a foam manifold may vary according to needs ofa prescribed therapy. For example, in some embodiments, the tissueinterface 108 may be a foam manifold having pore sizes in a range of400-600 microns. The tensile strength of the tissue interface 108 mayalso vary according to needs of a prescribed therapy. For example, thetensile strength of a foam may be increased for instillation of topicaltreatment solutions. In one non-limiting example, the tissue interface108 may be an open-cell, reticulated polyurethane foam such asGranuFoam® dressing or VeraFlo® foam, both available from KineticConcepts, Inc. of San Antonio, Tex.

The tissue interface 108 may be either hydrophobic or hydrophilic. In anexample in which the tissue interface 108 may be hydrophilic, the tissueinterface 108 may also wick fluid away from a tissue site, whilecontinuing to distribute negative pressure to the tissue site. Thewicking properties of the tissue interface 108 may draw fluid away froma tissue site by capillary flow or other wicking mechanisms. An exampleof a hydrophilic foam is a polyvinyl alcohol, open-cell foam such asV.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc. of SanAntonio, Tex. Other hydrophilic foams may include those made frompolyether. Other foams that may exhibit hydrophilic characteristicsinclude hydrophobic foams that have been treated or coated to providehydrophilicity.

The tissue interface 108 may further promote granulation at a tissuesite when pressure within the sealed therapeutic environment is reduced.For example, any or all of the surfaces of the tissue interface 108 mayhave an uneven, coarse, or jagged profile that can induce microstrainsand stresses at a tissue site if negative pressure is applied throughthe tissue interface 108.

In some embodiments, the tissue interface 108 may be constructed frombioresorbable materials. Suitable bioresorbable materials may include,without limitation, a polymeric blend of polylactic acid (PLA) andpolyglycolic acid (PGA). The polymeric blend may also include withoutlimitation polycarbonates, polyfumarates, and capralactones. The tissueinterface 108 may further serve as a scaffold for new cell-growth, or ascaffold material may be used in conjunction with the tissue interface108 to promote cell-growth. A scaffold is generally a substance orstructure used to enhance or promote the growth of cells or formation oftissue, such as a three-dimensional porous structure that provides atemplate for cell growth. Illustrative examples of scaffold materialsinclude calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites,carbonates, or processed allograft materials.

In some embodiments, the cover 106 may provide a bacterial barrier andprotection from physical trauma. The cover 106 may also be constructedfrom a material that can reduce evaporative losses and provide a fluidseal between two components or two environments, such as between atherapeutic environment and a local external environment. The cover 106may be, for example, an elastomeric film or membrane that can provide aseal adequate to maintain a negative pressure at a tissue site for agiven negative-pressure source. The cover 106 may have a highmoisture-vapor transmission rate (MVTR) in some applications. Forexample, the MVTR may be at least 300 g/m{circumflex over ( )}2 pertwenty-four hours in some embodiments. In some example embodiments, thecover 106 may be a polymer drape, such as a polyurethane film, that ispermeable to water vapor but impermeable to liquid. Such drapestypically have a thickness in the range of 25-50 microns. For permeablematerials, the permeability generally should be low enough that adesired negative pressure may be maintained. In some embodiments, thecover may be a drape such as drape 406 shown in FIG. 4 .

An attachment device may be used to attach the cover 106 to anattachment surface, such as undamaged epidermis, a gasket, or anothercover. The attachment device may take many forms. For example, anattachment device may be a medically-acceptable, pressure-sensitiveadhesive that extends about a periphery, a portion, or an entire sealingmember. In some embodiments, for example, some or all of the cover 106may be coated with an acrylic adhesive having a coating weight between25-65 grams per square meter (g.s.m.). Thicker adhesives, orcombinations of adhesives, may be applied in some embodiments to improvethe seal and reduce leaks. Other example embodiments of an attachmentdevice may include a double-sided tape, paste, hydrocolloid, hydrogel,silicone gel, or organogel.

In some embodiments, the dressing interface 107 may facilitate couplingthe negative-pressure source 104 to the dressing 102. The negativepressure provided by the negative-pressure source 104 may be deliveredthrough the conduit 135 to a negative-pressure interface, which mayinclude an elbow portion. In one illustrative embodiment, thenegative-pressure interface may be a T.R.A.C.® Pad or Sensa T.R.A.C.®Pad available from KCI of San Antonio, Tex. The negative-pressureinterface enables the negative pressure to be delivered through thecover 106 and to the tissue interface 108 and the tissue site. In thisillustrative, non-limiting embodiment, the elbow portion may extendthrough the cover 106 to the tissue interface 108, but numerousarrangements are possible.

A controller, such as the controller 110, may be a microprocessor orcomputer programmed to operate one or more components of the therapysystem 100, such as the negative-pressure source 104. In someembodiments, for example, the controller 110 may be a microcontroller,which generally comprises an integrated circuit containing a processorcore and a memory programmed to directly or indirectly control one ormore operating parameters of the therapy system 100. Operatingparameters may include the power applied to the negative-pressure source104, the pressure generated by the negative-pressure source 104, or thepressure distributed to the tissue interface 108, for example. Thecontroller 110 is also preferably configured to receive one or moreinput signals, such as a feedback signal, and programmed to modify oneor more operating parameters based on the input signals.

Sensors, such as the pressure sensor 120 or the electric sensor 124, aregenerally known in the art as any apparatus operable to detect ormeasure a physical phenomenon or property, and generally provide asignal indicative of the phenomenon or property that is detected ormeasured. For example, the pressure sensor 120 and the electric sensor124 may be configured to measure one or more operating parameters of thetherapy system 100. In some embodiments, the pressure sensor 120 may bea transducer configured to measure pressure in a pneumatic pathway andconvert the measurement to a signal indicative of the pressure measured.In some embodiments, for example, the pressure sensor 120 may be apiezoresistive strain gauge. The electric sensor 124 may optionallymeasure operating parameters of the negative-pressure source 104, suchas the voltage or current, in some embodiments. Preferably, the signalsfrom the pressure sensor 120 and the electric sensor 124 are suitable asan input signal to the controller 110, but some signal conditioning maybe appropriate in some embodiments. For example, the signal may need tobe filtered or amplified before it can be processed by the controller110. Typically, the signal is an electrical signal that is transmittedand/or received on by wire or wireless means, but may be represented inother forms, such as an optical signal.

The solution source 114 is representative of a container, canister,pouch, bag, or other storage component, which can provide a solution forinstillation therapy. Compositions of solutions may vary according to aprescribed therapy, but examples of solutions that may be suitable forsome prescriptions include hypochlorite-based solutions, silver nitrate(0.5%), sulfur-based solutions, biguanides, cationic solutions, andisotonic solutions. Examples of such other therapeutic solutions thatmay be suitable for some prescriptions include hypochlorite-basedsolutions, silver nitrate (0.5%), sulfur-based solutions, biguanides,cationic solutions, and isotonic solutions. In one illustrativeembodiment, the solution source 114 may include a storage component forthe solution and a separate cassette for holding the storage componentand delivering the solution to the tissue site 150, such as a V.A.C.VeraLink™ Cassette available from Kinetic Concepts, Inc. of San Antonio,Tex.

The container 112 may also be representative of a container, canister,pouch, or other storage component, which can be used to collect andmanage exudates and other fluids withdrawn from a tissue site. In manyenvironments, a rigid container such as, for example, a container 162,may be preferred or required for collecting, storing, and disposing offluids. In other environments, fluids may be properly disposed ofwithout rigid container storage, and a re-usable container could reducewaste and costs associated with negative-pressure therapy. In someembodiments, the container 112 may comprise a canister having acollection chamber, a first inlet fluidly coupled to the collectionchamber and a first outlet fluidly coupled to the collection chamber andadapted to receive negative pressure from a source of negative pressure.In some embodiments, a first fluid conductor may comprise a first membersuch as, for example, the conduit 135 fluidly coupled between the firstinlet and the tissue interface 108 by the negative-pressure interfacedescribed above, and a second member such as, for example, the conduit126 fluidly coupled between the first outlet and a source of negativepressure whereby the first conductor is adapted to provide negativepressure within the collection chamber to the tissue site.

The therapy system 100 may also comprise a flow regulator such as, forexample, a vent regulator 118 fluidly coupled to a source of ambient airto provide a controlled or managed flow of ambient air to the sealedtherapeutic environment provided by the dressing 102 and ultimately thetissue site. In some embodiments, the vent regulator 118 may control theflow of ambient fluid to purge fluids and exudates from the sealedtherapeutic environment. In some embodiments, the vent regulator 118 maybe fluidly coupled by a fluid conductor or vent conduit 145 through thedressing interface 107 to the tissue interface 108. The vent regulator118 may be configured to fluidly couple the tissue interface 108 to asource of ambient air as indicated by a dashed arrow. In someembodiments, the vent regulator 118 may be disposed within the therapysystem 100 rather than being proximate to the dressing 102 so that theair flowing through the vent regulator 118 is less susceptible toaccidental blockage during use. In such embodiments, the vent regulator118 may be positioned proximate the container 112 and/or proximate asource of ambient air where the vent regulator 118 is less likely to beblocked during usage.

In operation, the tissue interface 108 may be placed within, over, on,or otherwise proximate a tissue site, such as tissue site 150. The cover106 may be placed over the tissue interface 108 and sealed to anattachment surface near the tissue site 150. For example, the cover 106may be sealed to undamaged epidermis peripheral to a tissue site. Thus,the dressing 102 can provide a sealed therapeutic environment proximateto a tissue site, substantially isolated from the external environment,and the negative-pressure source 104 can reduce the pressure in thesealed therapeutic environment. Negative pressure applied across thetissue site through the tissue interface 108 in the sealed therapeuticenvironment can induce macrostrain and microstrain in the tissue site,as well as remove exudates and other fluids from the tissue site, whichcan be collected in container 112.

In one embodiment, the controller 110 may receive and process data, suchas data related to the pressure distributed to the tissue interface 108from the pressure sensor 120. The controller 110 may also control theoperation of one or more components of therapy system 100 to manage thepressure distributed to the tissue interface 108 for application to thewound at the tissue site 150, which may also be referred to as the woundpressure (WP). In one embodiment, controller 110 may include an inputfor receiving a desired target pressure (TP) set by a clinician or otheruser and may be program for processing data relating to the setting andinputting of the target pressure (TP) to be applied to the tissue site150. In one example embodiment, the target pressure (TP) may be a fixedpressure value determined by a user/caregiver as the reduced pressuretarget desired for therapy at the tissue site 150 and then provided asinput to the controller 110. The user may be a nurse or a doctor orother approved clinician who prescribes the desired negative pressure towhich the tissue site 150 should be applied. The desired negativepressure may vary from tissue site to tissue site based on the type oftissue forming the tissue site 150, the type of injury or wound (ifany), the medical condition of the patient, and the preference of theattending physician. After selecting the desired target pressure (TP),the negative-pressure source 104 is controlled to achieve the targetpressure (TP) desired for application to the tissue site 150.

Referring more specifically to FIG. 2A, a graph illustrating anillustrative embodiment of pressure control modes 200 that may be usedfor the negative-pressure and instillation therapy system of FIG. 1 isshown wherein the x-axis represents time in minutes (min) and/or seconds(sec) and the y-axis represents pressure generated by a pump in Torr(mmHg) that varies with time in a continuous pressure mode and anintermittent pressure mode that may be used for applying negativepressure in the therapy system. The target pressure (TP) may be set bythe user in a continuous pressure mode as indicated by solid line 201and dotted line 202 wherein the wound pressure (WP) is applied to thetissue site 150 until the user deactivates the negative-pressure source104. The target pressure (TP) may also be set by the user in anintermittent pressure mode as indicated by solid lines 201, 203 and 205wherein the wound pressure (WP) is cycled between the target pressure(TP) and atmospheric pressure. For example, the target pressure (TP) maybe set by the user at a value of 125 mmHg for a specified period of time(e.g., 5 min) followed by the therapy being turned off for a specifiedperiod of time (e.g., 2 min) as indicated by the gap between the solidlines 203 and 205 by venting the tissue site 150 to the atmosphere, andthen repeating the cycle by turning the therapy back on as indicated bysolid line 205 which consequently forms a square wave pattern betweenthe target pressure (TP) level and atmospheric pressure. In someembodiments, the ratio of the “on-time” to the “off-time” or the total“cycle time” may be referred to as a pump duty cycle (PD).

In some example embodiments, the decrease in the wound pressure (WP) atthe tissue site 150 from ambient pressure to the target pressure (TP) isnot instantaneous, but rather gradual depending on the type of therapyequipment and dressing being used for the particular therapy treatment.For example, the negative-pressure source 104 and the dressing 102 mayhave an initial rise time as indicated by the dashed line 207 that mayvary depending on the type of dressing and therapy equipment being used.For example, the initial rise time for one therapy system may be in therange between about 20-30 mmHg/second or, more specifically, equal toabout 25 mmHg/second, and in the range between about 5-10 mmHg/secondfor another therapy system. When the therapy system 100 is operating inthe intermittent mode, the repeating rise time as indicated by the solidline 205 may be a value substantially equal to the initial rise time asindicated by the dashed line 207.

The target pressure may also be a variable target pressure (VTP)controlled or determined by controller 110 that varies in a dynamicpressure mode. For example, the variable target pressure (VTP) may varybetween a maximum and minimum pressure value that may be set as an inputdetermined by a user as the range of negative pressures desired fortherapy at the tissue site 150. The variable target pressure (VTP) mayalso be processed and controlled by controller 110 that varies thetarget pressure (TP) according to a predetermined waveform such as, forexample, a sine waveform or a saw-tooth waveform or a triangularwaveform, that may be set as an input by a user as the predetermined ortime-varying reduced pressures desired for therapy at the tissue site150.

Referring more specifically to FIG. 2B, a graph illustrating anillustrative embodiment of another pressure control mode for thenegative-pressure and instillation therapy system of FIG. 1 is shownwherein the x-axis represents time in minutes (min) and/or seconds (sec)and the y-axis represents pressure generated by a pump in Torr (mmHg)that varies with time in a dynamic pressure mode that may be used forapplying negative pressure in the therapy system. For example, thevariable target pressure (VTP) may be a reduced pressure that providesan effective treatment by applying reduced pressure to tissue site 150in the form of a triangular waveform varying between a minimum andmaximum pressure of 50-125 mmHg with a rise time 212 set at a rate of+25 mmHg/min. and a descent time 211 set at −25 mmHg/min, respectively.In another embodiment of the therapy system 100, the variable targetpressure (VTP) may be a reduced pressure that applies reduced pressureto tissue site 150 in the form of a triangular waveform varying between25-125 mmHg with a rise time 212 set at a rate of +30 mmHg/min and adescent time 211 set at −30 mmHg/min. Again, the type of system andtissue site determines the type of reduced pressure therapy to be used.

FIG. 3 is a flow chart illustrating an illustrative embodiment of atherapy method 300 that may be used for providing negative-pressure andinstillation therapy for delivering an antimicrobial solution or othertreatment solution to a dressing at a tissue site. In one embodiment,the controller 110 receives and processes data, such as data related tofluids provided to the tissue interface 108. Such data may include thetype of instillation solution prescribed by a clinician, the volume offluid or solution to be instilled to the tissue site (“fill volume”),and the amount of time needed to soak the tissue interface (“soak time”)before applying a negative pressure to the tissue site. The fill volumemay be, for example, between 10 and 500 mL, and the soak time may bebetween one second to 30 minutes. The controller 110 may also controlthe operation of one or more components of the therapy system 100 tomanage the instillation fluids delivered from the solution source 114 tothe tissue site 150 for cleaning and/or providing therapy treatment tothe wound along with the negative pressure therapy as described above.In one embodiment, fluid may be instilled to the tissue site 150 byapplying a negative pressure from the negative-pressure source 104 toreduce the pressure at the tissue site 150 and draw the instillationfluid into the dressing 102 as indicated at 302 and described above inmore detail. In another embodiment, fluid may be instilled to the tissuesite 150 by applying a positive pressure from the negative-pressuresource 104 (not shown) or the instillation pump 116 to force theinstillation fluid from the solution source 114 to the tissue interface108 as indicated at 304. In yet another embodiment, fluid may beinstilled to the tissue site 150 by elevating the solution source 114 toheight sufficient to force the instillation fluid into the tissueinterface 108 by the force of gravity as indicated at 306. Thus, thetherapy method 300 includes instilling fluid into the tissue interface108 by either drawing or forcing the fluid into the tissue interface 108as indicated at 310.

The therapy method 300 may control the fluid dynamics of applying thefluid solution to the tissue interface 108 at 312 by providing acontinuous flow of fluid at 314 or an intermittent flow of fluid forsoaking the tissue interface 108 at 316. The therapy method 300 mayinclude the application of negative pressure to the tissue interface 108to provide either the continuous flow or intermittent soaking flow offluid at 320. The application of negative pressure may be implemented toprovide a continuous pressure mode of operation at 322 as describedabove to achieve a continuous flow rate of instillation fluid throughthe tissue interface 108 or a dynamic pressure mode of operation at 324as described above to vary the flow rate of instillation fluid throughthe tissue interface 108. Alternatively, the application of negativepressure may be implemented to provide an intermittent mode of operationat 326 as described above to allow instillation fluid to soak into thetissue interface 108 as described above. In the intermittent mode, aspecific fill volume and the soak time may be provided depending, forexample, on the type of wound being treated and the type of dressing 102being utilized to treat the wound. After or during instillation of fluidinto the tissue interface 108 has been completed, the therapy method 300may begin may be utilized using any one of the three modes of operationat 330 as described above. The controller 110 may be utilized to selectany one of these three modes of operation and the duration of thenegative pressure therapy as described above before commencing anotherinstillation cycle at 340 by instilling more fluid at 310.

As discussed above, the tissue site 150 may include, without limitation,any irregularity with a tissue, such as an open wound, surgicalincision, or diseased tissue. The therapy system 100 is presented in thecontext of a tissue site that includes a wound that may extend throughthe epidermis and the dermis, and may reach into the hypodermis orsubcutaneous tissue. The therapy system 100 may be used to treat a woundof any depth, as well as many different types of wounds including openwounds, incisions, or other tissue sites. The tissue site 150 may be thebodily tissue of any human, animal, or other organism, including bonetissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue,connective tissue, cartilage, tendons, ligaments, or any other tissue.Treatment of the tissue site 150 may include removal of fluidsoriginating from the tissue site 150, such as exudates or ascites, orfluids instilled into the dressing to cleanse or treat the tissue site150, such as antimicrobial solutions.

As indicated above, the therapy system 100 may be packaged as a single,integrated unit such as a therapy system including all of the componentsshown in FIG. 1 that are fluidly coupled to the dressing 102. In someembodiments, an integrated therapy unit may include thenegative-pressure source 104, the controller 110, the pressure sensor120, and the container 112 which may be fluidly coupled to the dressinginterface 107. In this therapy unit, the negative-pressure source 104 isindirectly coupled to the dressing interface 107 through the container112 by conduit 126 and conduit 135, and the pressure sensor 120 isindirectly coupled to the dressing interface 107 by conduit 121 andconduit 155 as described above. In some embodiments, the negativepressure conduit 135 and the pressure sensing conduit 155 may becombined in a single fluid conductor that can be, for example, amulti-lumen tubing comprising a central primary lumen that functions asthe negative pressure conduit 135 for delivering negative pressure tothe dressing interface 107 and several peripheral auxiliary lumens thatfunction as the pressure sensing conduit 155 for sensing the pressurethat the dressing interface 107 delivers to the tissue interface 108. Inthis type of therapy unit wherein the pressure sensor 120 is removedfrom and indirectly coupled to the dressing interface 107, the negativepressure measured by the pressure sensor 120 may be different from thewound pressure (WP) actually being applied to the tissue site 150. Suchpressure differences must be approximated in order to adjust thenegative-pressure source 104 to deliver the pump pressure (PP) necessaryto provide the desired or target pressure (TP) to the tissue interface108. Moreover, such pressure differences and predictability may beexacerbated by viscous fluids such as exudates being produced by thetissue site or utilizing a single therapy device including a pressuresensor to deliver negative pressure to multiple tissue sites on a singlepatient.

What is needed is a pressure sensor that is integrated within thedressing interface 107 so that the pressure sensor is proximate thetissue interface 108 when disposed on the tissue site in order toprovide a more accurate reading of the wound pressure (WP) beingprovided within the therapy environment of the dressing 102. Theintegrated pressure sensor may be used with or without the remotepressure sensor 120 that is indirectly coupled to the dressing interface107. In some example embodiments, the dressing interface 107 maycomprise a housing having a therapy cavity that opens to the tissue sitewhen positioned thereon. The integrated pressure sensor may have asensing portion disposed within the therapy cavity along with othersensors including, for example, a temperature sensor, a humidity sensor,and a pH sensor. The sensors may be electrically coupled to thecontroller 110 outside the therapy cavity to provide data indicative ofthe pressure, temperature, humidity, and acidity properties within thetherapeutic space of the therapy cavity. The sensors may be electricallycoupled to the controller 110, for example, by wireless means. Systems,apparatuses, and methods described herein provide the advantage of moreaccurate measurements of these properties, as well as other significantadvantages described below in more detail.

As indicated above, the dressing 102 may include the cover 106, thedressing interface 107, and the tissue interface 108. Referring now toFIGS. 4, 5A, 5B, 5C, 6A, 6B, and 7, a first dressing is shown comprisinga dressing interface 400, a cover or drape 406, and a tissue interfaceor manifold 408 disposed adjacent a tissue site 410, all of which may befunctionally similar in part to the dressing interface 107, the cover106, and the tissue interface 108, respectively, as described above. Inone example embodiment, the dressing interface 400 may comprise ahousing 401 and a wall 402 disposed within the housing 401 wherein thewall 402 forms a recessed space or a therapy cavity 403 that opens tothe manifold 408 when disposed at the tissue site 410 and a componentcavity 404 opening away from the tissue site 410 of the upper portion ofthe dressing interface 400. In some embodiments, sensing portions ofvarious sensors may be disposed within the therapy cavity 403, andelectrical devices associated with the sensors may be disposed withinthe component cavity 404 and electrically coupled to the sensingportions through the wall 402. Electrical devices disposed within thecomponent cavity 404 may include components associated with some exampleembodiments of the therapy system of FIG. 1 . Although the dressinginterface 400 and the therapy cavity 403 are functionally similar to thedressing interface 107 as described above, the dressing interface 400further comprises the wall 402, the sensors, and the associatedelectrical devices described below in more detail. In some embodiments,the housing 401 may further comprise a neck portion or neck 407 fluidlycoupled to a conduit 405. In some embodiments, the housing 401 mayfurther comprise a flange portion or flange 409 having flow channels(see FIG. 8 ) configured to be fluidly coupled to the therapy cavity 403when disposed on the manifold 408.

In some example embodiments, the neck 407 of the housing 401 may includeportions of both the therapy cavity 403 and the component cavity 404.That portion of the neck 407 extending into the therapy cavity 403 isfluidly coupled to the conduit 405, while the portion extending into thecomponent cavity 404 may contain some of the electrical devices. In someexample embodiments, the conduit 405 may comprise a primary lumen or anegative pressure lumen 430 and separate auxiliary lumens such as, forexample, an instillation lumen 433 and a venting lumen 435 fluidlycoupled by the neck 407 of the housing 401 to the therapy cavity 403.The negative pressure lumen 430 is similar to the negative pressureconduit 135 that may be coupled indirectly to the negative-pressuresource 104. The venting lumen 435 is similar to the vent conduit 145that may be fluidly coupled to the vent regulator 118 for purging fluidsfrom the therapy cavity 403. The instillation lumen 433 is similar tothe instillation conduit 133 that may be fluidly coupled directly orindirectly to the solution source 114 for flushing fluids from thetherapy cavity 403 for removal by the application of negative pressurethrough the negative pressure lumen 430.

In some embodiments, the component cavity 404 containing the electricaldevices may be open to the ambient environment such that the electricaldevices are exposed to the ambient environment. In other exampleembodiments, the component cavity 404 may be closed by a cover such as,for example, a cap 411 to protect the electrical devices. In still otherembodiments, the component cavity 404 covered by the cap 411 may stillbe vented to the ambient environment to provide cooling to theelectrical devices and a source of ambient pressure for a pressuresensor disposed in the therapy cavity 403 as described in more detailbelow. The first dressing interface 400 may further comprise a drapering 413 covering the circumference of the flange 409 and the adjacentportion of the drape 406 to seal the therapy cavity 403 of the housing401 over the manifold 408 and the tissue site 410. In some embodiments,the drape ring 413 may comprise a polyurethane film including and anattachment device such as, for example, an acrylic, polyurethane gel,silicone, or hybrid combination of the foregoing adhesives (not shown)to attach the drape ring 413 to the flange 409 and the drape 406. Theattachment device of drape ring 413 may be a single element of siliconor hydrocolloid with the adhesive on each side that functions as agasket between the drape 406 and the flange 409. In some embodiments,the drape ring 413 may be similar to the cover 106 and/or the attachmentdevice described above in more detail.

In some embodiments, a pressure sensor 416, a temperature and humiditysensor 418, and a pH sensor 420 (collectively referred to below as “thesensors”) may be disposed in the housing 401 with each one having asensing portion extending into the therapy cavity 403 of the housing 401and associated electronics disposed within the component cavity 404. Thehousing 401 may include other types of sensors, or combinations of theforegoing sensors, such as, for example, oxygen sensors. In some exampleembodiments, the sensors may be coupled to or mounted on the wall 402and electrically coupled to electrical components and circuits disposedwithin the component cavity 404 by electrical conductors extendingthrough the wall 402. In some preferred embodiments, the electricalconductors extend through pathways in the wall 402 while keeping thetherapy cavity 403 electrically and pneumatically isolated from thecomponent cavity 404. For example, the wall 402 may comprise a circuitboard 432 on which the electrical circuits and/or components may beprinted or mounted. In some other examples, the circuit board 432 may bethe wall 402 that covers an opening between the therapy cavity 403 andthe component cavity 404, and pneumatically seals the therapy cavity 403from the component cavity 404 when seated over the opening.

In some embodiments, the electrical circuits and/or componentsassociated with the sensors that are mounted on the circuit board 432within the component cavity 404 may be electrically coupled to thecontroller 110 to interface with the rest of the therapy system 100 asdescribed above. In some embodiments, for example, the electricalcircuits and/or components may be electrically coupled to the controller110 by a conductor that may be a component of the conduit 405. In someother preferred embodiments, a communications module 422 may be disposedin the component cavity 404 of the housing 401 and mounted on thecircuit board 432 within the component cavity 404. Using a wirelesscommunications module 422 has the advantage of eliminating an electricalconductor between the dressing interface 400 and the integrated portionof the therapy system 100 that may become entangled with the conduit 405when in use during therapy treatments. For example, the electricalcircuits and/or components associated with the sensors along with theterminal portion of the sensors may be electrically coupled to thecontroller 110 by wireless means such as an integrated deviceimplementing Bluetooth® Low Energy wireless technology. Morespecifically, the communications module 422 may be a Bluetooth® LowEnergy system-on-chip that includes a microprocessor (an example of themicroprocessors referred to hereinafter) such as the nRF51822 chipavailable from Nordic Semiconductor. The wireless communications module422 may be implemented with other wireless technologies suitable for usein the medical environment.

In some embodiments, a voltage regulator 423 for signal conditioning anda power source 424 may be disposed within the component cavity 404 ofthe housing 401, and mounted on the circuit board 432. The power source424 may be secured to the circuit board 432 by a bracket 426. The powersource 424 may be, for example, a battery that may be a coin batteryhaving a low-profile that provides a 3-volt source for thecommunications module 422 and the other electronic components within thecomponent cavity 404 associated with the sensors. In some exampleembodiments, the sensors, the electrical circuits and/or componentsassociated with the sensors, the wall 402 and/or the circuit board 432,the communications module 422, and the power source 424 may beintegrated into a single package and referred to hereinafter as a sensorassembly 425 as shown in FIG. 6B. In some preferred embodiments, thewall 402 of the sensor assembly 425 may be the circuit board 432 itselfas described above that provides a seal between tissue site 410 and theatmosphere when positioned over the opening between the therapy cavity403 and the component cavity 404 of the housing 401 and functions as thewall 402 within the housing 401 that forms the therapy cavity 403.

Referring now to FIGS. 8A and 8B, a perspective view and a bottom view,respectively, of a bottom surface of the flange 409 facing the manifold408 is shown. In some embodiments, the bottom surface may comprisefeatures or channels to direct the flow of liquids and/or exudates awayfrom the sensors out of the therapy cavity 403 into the negativepressure lumen 430 when negative pressure is being applied to thetherapy cavity 403. In some embodiments, these channels may be moldedinto the bottom surface of the flange 409 to form a plurality ofserrated guide channels 437, perimeter collection channels 438, andintermediate collection channels 439. The serrated guide channels 437may be positioned and oriented in groups on bottom surface to directlycapture and channel at least half of the liquids being drawn into thetherapy cavity 403 with the groups of serrated guide channels 437, andindirectly channel a major portion of the balance of the liquids beingdrawn into the therapy cavity 403 between the groups of serrated guidechannels 437. In addition, perimeter collection channels 438 andintermediate collection channels 439 redirect the flow of liquids thatare being drawn in between the groups of radially-oriented serratedguide channels 437 into the guide channels 437. An example of thisredirected flow is illustrated by bolded flow arrows 436. In someexample embodiments, a portion of the housing 401 within the therapycavity 403 may comprise a second set of serrated guide channels 427spaced apart and radially-oriented to funnel liquids being drawn intothe therapy cavity 403 from the flange 409 into the negative pressurelumen 430. In other example embodiments of the bottom surface of theflange 409 and that portion of the housing 401 within the therapy cavity403, the channels may be arranged in different patterns.

As indicated above, the sensor assembly 425 may comprise a pressuresensor 416, a humidity sensor 418, a temperature sensor as a componentof either the pressure sensor 416 or the humidity sensor 418, and a pHsensor 420. Each of the sensors may comprise a sensing portion extendinginto the therapy cavity 403 of the housing 401 and a terminal portionelectrically coupled to the electrical circuits and/or components withinthe component cavity 404. Referring more specifically to FIGS. 4, 6A,6B, and 7A-7D, the housing 401 may comprise a sensor bracket 441 thatmay be a molded portion of the housing 401 within the therapy cavity 403in some embodiments. The sensor bracket 441 may be structured to houseand secure the pressure sensor 416 on the circuit board 432 within thetherapy cavity 403 of the sensor assembly 425 that provides a sealbetween tissue site 410 and the atmosphere as described above. In someembodiments, the pressure sensor 416 may be a differential gaugecomprising a sensing portion 442 and a terminal portion or vent 443. Thevent 443 of the pressure sensor 416 may be fluidly coupled through thecircuit board 432 to the component cavity 404 and the atmosphere by avent hole 444 extending through the circuit board 432. Because thecomponent cavity 404 is vented to the ambient environment, the vent 443of the pressure sensor 416 is able to measure the wound pressure (WP)with reference to the ambient pressure. The sensing portion 442 of thepressure sensor 416 may be positioned in close proximity to the manifold408 to optimize fluid coupling and accurately measure the wound pressure(WP) at the tissue site 410. In some embodiments, the pressure sensor416 may be a piezo-resistive pressure sensor having a pressure sensingelement covered by a dielectric gel such as, for example, a Model TE1620 pressure sensor available from TE Connectivity. The dielectric gelprovides electrical and fluid isolation from the blood and woundexudates in order to protect the sensing element from corrosion or otherdegradation. This allows the pressure sensor 416 to measure the woundpressure (WP) directly within the therapy cavity 403 of the housing 401proximate to the manifold 408 as opposed to measuring the wound pressure(WP) from a remote location. In some embodiments, the pressure sensor416 may be a gauge that measures the absolute pressure that does notneed to be vented.

In some embodiments, the pressure sensor 416 also may comprise atemperature sensor for measuring the temperature at the tissue site 410.In other embodiments, the humidity sensor 418 may comprise a temperaturesensor for measuring the temperature at the tissue site 410. The sensorbracket 441 also may be structured to support the humidity sensor 418 onthe circuit board 432 of the sensor assembly 425. In some embodiments,the humidity sensor 418 may comprise a sensing portion that iselectrically coupled through the circuit board 432 to a microprocessormounted on the other side of the circuit board 432 within the componentcavity 404. The sensing portion of the humidity sensor 418 may befluidly coupled to the space within the therapy cavity 403 that includesa fluid pathway 445 extending from the therapy cavity 403 into thenegative pressure lumen 430 of the conduit 405 as indicated by the boldarrow to sense both the humidity and the temperature. The sensingportion of the humidity sensor 418 may be positioned within the fluidpathway 445 to limit direct contact with bodily fluids being drawn intothe negative pressure lumen 430 from the tissue site 410. In someembodiments, the space within the therapy cavity 403 adjacent thesensing portion of the humidity sensor 418 may be purged by venting thespace through the venting lumen 435 as described in more detail below.The space may also be flushed by instilling fluids into the spacethrough the instillation lumen 433. As indicated above, the humiditysensor 418 may further comprise a temperature sensor (not shown) as thelocation within the fluid pathway 445 is well-suited to achieve accuratereadings of the temperature of the fluids. In some embodiments, thehumidity sensor 418 that comprises a temperature sensor may be a singleintegrated device such as, for example, Model TE HTU21D(F) humiditysensor also available from TE Connectivity.

Referring now to FIGS. 9A and 9B, the pH sensor 420 may comprise asensing portion disposed within the therapy cavity 403 that iselectrically coupled through the circuit board 432 to a front-endamplifier 421 mounted on the other side of the circuit board 432 withinthe component cavity 404. The front-end amplifier 421 comprises analogsignal conditioning circuitry that includes sensitive analog amplifierssuch as, for example, operational amplifiers, filters, andapplication-specific integrated circuits. The front-end amplifier 421measures minute voltage potential changes provided by the sensingportions to provide an output signal indicative of the pH of the fluids.The sensing portion of the pH sensor 420 may be fluidly coupled to thespace within the therapy cavity 403 by being positioned in the fluidpathway 445 that extends into the negative pressure lumen 430 asdescribed above to sense the pH changes. The sensing portion of the pHsensor 420 may be formed and positioned within the fluid pathway 445 sothat the sensing portion directly contacts the wound fluid withoutcontacting the wound itself so that the sensing portion of the pH sensor420 does not interfere with the wound healing process. In someembodiments, the space within the therapy cavity 403 adjacent thesensing portion of the pH sensor 420 also may be purged by venting thespace through the venting lumen 435 as described in more detail below.The space may also be flushed by instilling fluids into the spacethrough the instillation lumen 433. In some embodiments, the pH sensor420 may be, for example, pH sensor 450 shown in FIG. 9A that comprises apair of printed medical electrodes including a working electrode 451 anda reference electrode 452. In some embodiments, the working electrode451 may have a node being substantially circular in shape at one end andhaving a terminal portion at the other end, and the reference electrode452 may have a node being substantially semicircular in shape anddisposed around the node of the working electrode 451.

In some example embodiments, the working electrode 451 may comprise amaterial selected from a group including graphene oxide ink, conductivecarbon, carbon nanotube inks, silver, nano-silver, silver chloride ink,gold, nano-gold, gold-based ink, metal oxides, conductive polymers, or acombination thereof. This working electrode 451 further comprise acoating or film applied over the material wherein such coating or filmmay be selected from a group including metal oxides such as, forexample, tungsten, platinum, iridium, ruthenium, and antimony oxides, ora group of conductive polymers such as polyaniline and others so thatthe conductivity of the working electrode 451 changes based on changesin hydrogen ion concentration of the fluids being measured or sampled.In some example embodiments, the reference electrode 452 may comprise amaterial selected from a group including silver, nano-silver, silverchloride ink, or a combination thereof. The pH sensor 450 may furthercomprise a coating 453 covering the electrodes that insulates andisolates the working electrode 451 from the reference electrode 452except in the electrical conductive space 454. In some embodiments, thecoating 453 does not completely cover the terminal portions of theworking electrode 451 and the reference electrode 452 and form terminals455 and 456, respectively. The terminals 455 and 456 may be electricallycoupled to the front-end amplifier 421. In some embodiments, theterminals 455 and 456 may be electrically coupled to the front-endamplifier 421.

In some example embodiments, the terminal portion of the workingelectrode 451 and the reference electrode 452 may extend through thecircuit board 432 and electrically coupled to the front-end amplifier421 of the pH sensor 450. As indicated above, the front-end amplifier421 of the pH sensor 450 measures minute potential changes between theworking electrode 451 and the reference electrode 452 that result from achange in hydrogen ion concentration of the wound fluid as the pH of thewound fluid changes. The front-end amplifier 421 may be, for example, anextremely accurate voltmeter that measures the voltage potential betweenthe working electrode 451 and the reference electrode 452. The front-endamplifier 421 may be for example a high impedance analog front-end (AFE)device such as the LMP7721 and LMP91200 chips that are available frommanufacturers such as Texas Instruments or the AD7793 and AD8603 chipsthat are available from manufacturers such as Analog Devices.

In some other embodiments, the pH sensor 420 may include a thirdelectrode such as, for example, pH sensor 460 shown in FIG. 9B thatcomprises a third electrode or a counter electrode 462 in addition tothe working electrode 451 and the reference electrode 452 of the pHsensor 450. The counter electrode 462 also comprises a node partiallysurrounding the node of the working electrode 451 and a terminal 466adapted to be electrically coupled to the front-end amplifier 421.Otherwise, the pH sensor 460 is substantially similar to the pH sensor450 described above as indicated by the reference numerals. The counterelectrode 462 is also separated from the working electrode 451 and isalso insulated from the wound fluid and the other electrodes by thecoating 453 except in the electrical conductive space 454. The counterelectrode 462 may be used in connection with the working electrode 451and the reference electrode 452 for the purpose of error correction ofthe voltages being measured. For example, the counter electrode 462 maypossess the same voltage potential as the potential of the workingelectrode 451 except with an opposite sign so that any electrochemicalprocess affecting the working electrode 451 will be accompanied by anopposite electrochemical process on the counter electrode 462. Althoughvoltage measurements are still being taken between the working electrode451 and the reference electrode 452 by the analog front end device ofthe pH sensor 460, the counter electrode 462 may be used for such errorcorrection and may also be used for current readings associated with thevoltage measurements. Custom printed electrodes assembled in conjunctionwith a front-end amplifier may be used to partially comprise pH sensorssuch as the pH sensor 450 and the pH sensor 460 may be available fromseveral companies such as, for example, GSI Technologies, Inc. andDropsens.

The systems, apparatuses, and methods described herein may provide othersignificant advantages. For example, some therapy systems are a closedsystem wherein the pneumatic pathway is not vented to ambient air, butrather controlled by varying the supply pressure (SP) to achieve thedesired target pressure (TP) in a continuous pressure mode, anintermittent pressure mode, or a variable target pressure mode asdescribed above in more detail with reference to FIGS. 2A and 2B. Insome embodiments of the closed system, the wound pressure (WP) beingmeasured in the dressing interface 107 may not drop in response to adecrease in the supply pressure (SP) as a result of a blockage withinthe dressing interface 107 or other portions of the pneumatic pathway.In some embodiments of the closed system, the supply pressure (SP) maynot provide airflow to the tissue interface 108 frequently enough thatmay result in the creation of a significant head pressure or blockageswithin the dressing interface 107 that also would interfere with sensormeasurements being taken by the dressing interface 400 as describedabove. The head pressure in some embodiments may be defined as adifference in pressure (DP) between a negative pressure set by a user orcaregiver for treatment, i.e., the target pressure (TP), and thenegative pressure provided by a negative pressure source that isnecessary to offset the pressure drop inherent in the fluid conductors,i.e., the supply pressure (SP), in order to achieve or reach the targetpressure (TP). For example, the head pressure that a negative pressuresource needs to overcome may be as much as 75 mmHg. Problems may occurin such closed systems when a blockage occurs in the pneumatic pathwayof the fluid conductors that causes the negative pressure source toincrease to a value above the normal supply pressure (SP) as a result ofthe blockage. For example, if the blockage suddenly clears, theinstantaneous change in the pressure being supplied may cause harm tothe tissue site.

Some therapy systems have attempted to compensate for head pressure byintroducing a supply of ambient air flow into the therapeuticenvironment, e.g., the therapy cavity 403, by providing a vent with afilter on the housing 401 of the dressing interface 400 to provideambient air flow into the therapeutic environment as a controlled leak.However, in some embodiments, the filter may be blocked when theinterface dressing is applied to the tissue site or when asked at leastblocked during use. Locating the filter in such a location may also beproblematic because it is more likely to be contaminated or compromisedby other chemicals and agents associated with treatment utilizinginstillation fluids that could adversely affect the performance of thefilter and the vent itself.

The embodiments of the therapy systems described herein overcome theproblems associated with having a large head pressure in a closedpneumatic environment, and the problems associated with using a ventdisposed on or adjacent the dressing interface. More specifically, theembodiments of the therapy systems described above comprise a pressuresensor, such as the pressure sensor 416, disposed within the pneumaticenvironment, i.e., in situ, that independently measures the woundpressure (WP) within the therapy cavity 403 of the housing 401 asdescribed above rather than doing so remotely. Consequently, thepressure sensor 416 is able to instantaneously identify dangerously highhead pressures and/or blockages within the therapy cavity 403 adjacentthe manifold 408. Because the auxiliary lumens are not being used forpressure sensing, the venting lumen 435 may be fluidly coupled to afluid regulator such as, for example, the vent regulator 118 in FIG. 1 ,that may remotely vent the therapeutic environment within the therapycavity 403 to the ambient environment or fluidly couple the therapeuticenvironment to a source of positive pressure. The vent regulator 118 maythen be used to provide ambient air or positive pressure to thetherapeutic environment in a controlled fashion to “purge” thetherapeutic environment within both the therapy cavity 403 and thenegative pressure lumen 430 to resolve the problems identified aboveregarding head pressures and blockages, and to facilitate thecontinuation of temperature, humidity, and pH measurements as describedabove.

Using a regulator to purge the therapeutic environment is especiallyimportant in therapy systems such as those disclosed in FIGS. 1 and 3that provide both negative pressure therapy and instillation therapy fordelivering therapeutic fluids to a tissue site. For example, in oneembodiment, therapeutic fluid may be instilled to the tissue site 150 byapplying a negative pressure from the negative-pressure source 104 toreduce the pressure at the tissue site 150 to draw the therapeutic fluidinto the dressing 102 as indicated at 302. In another embodiment,therapeutic fluid may be instilled to the tissue site 150 by applying apositive pressure from the negative-pressure source 104 (not shown) orthe instillation pump 116 to force the therapeutic fluid from thesolution source 114 to the tissue interface 108 as indicated at 304.Such embodiments may not be sufficient to remove all the therapeuticfluid from the therapeutic environment, or may not be sufficient toremove the therapeutic fluid quickly enough from the therapeuticenvironment to facilitate the continuation of accurate temperature,humidity, and pH measurements. Thus, the venting lumen 435 may be usedto provide ambient air or positive pressure to the therapeuticenvironment to more completely or quickly purge the therapeuticenvironment to obtain the desired measurements as described above.

In embodiments of therapy systems that include an air flow regulatorcomprising a valve such as the solenoid valve described above, the valveprovides controlled airflow venting or positive pressure to the therapycavity 403 as opposed to a constant airflow provided by a closed systemor an open system including a filter in response to the wound pressure(WP) being sensed by the pressure sensor 416. The controller 110 may beprogrammed to periodically open the solenoid valve as described aboveallowing ambient air to flow into the therapy cavity 403, or applying apositive pressure into the therapy cavity 403, at a predetermined flowrate and/or for a predetermined duration of time to purge the pneumaticsystem including the therapy cavity 403 and the negative pressure lumen430 of bodily liquids and exudates so that the humidity sensor 418 andthe pH sensor 420 provide more accurate readings and in a timelyfashion. This feature allows the controller to activate the solenoidvalve in a predetermined fashion to purge blockages and excess liquidsthat may develop in the fluid pathways or the therapy cavity 403 duringoperation. In some embodiments, the controller may be programmed to openthe solenoid valve for a fixed period of time at predetermined intervalssuch as, for example, for five seconds every four minutes to mitigatethe formation of any blockages.

In some other embodiments, the controller may be programmed to open thesolenoid valve in response to a stimulus within the pneumatic systemrather than, or additionally, being programmed to function on apredetermined therapy schedule. For example, if the pressure sensor isnot detecting pressure decay in the canister, this may be indicative ofa column of fluid forming in the fluid pathway or the presence of ablockage in the fluid pathway. Likewise, the controller may beprogrammed to recognize that an expected drop in canister pressure as aresult of the valve opening may be an indication that the fluid pathwayis open. The controller may be programmed to conduct such testsautomatically and routinely during therapy so that the patient orcaregiver can be forewarned of an impending blockage. The controller mayalso be programmed to detect a relation between the extent of thedeviation in canister pressure resulting from the opening of the valveand the volume of fluid with in the fluid pathway. For example, if thepressure change within the canister is significant when measured, thiscould be an indication that there is a significant volume of fluidwithin the fluid pathway. However, if the pressure change within thecanister is not significant, this could be an indication that the plenumvolume was larger.

The systems, apparatuses, and methods described herein may provideadditional advantages related to the instillation of cleansing and/ortherapeutic solutions to the therapy cavity 403. Using a source offluids such as, for example, solution source 114 to flush thetherapeutic environment is especially important in therapy systems suchas those disclosed in FIGS. 1 and 3 that provide both negative pressuretherapy and instillation therapy for delivering therapeutic fluids to atissue site. For example, the sensors are disposed within the therapycavity 403 and consequently exposed and in direct conflict with woundfluids and exudates that have the potential for fouling the sensors sothat they do not provide reliable data over a period of time duringwhich therapy is being provided. Moreover, fouling the sensors may alsodisable the sensors and/or degrade the calibration of the sensors suchthat they no longer accurately analyze the wound fluid to provide dataindicating the current state of the wound. Additionally, some of thesensors such as, for example, the pH sensor 420 comprisingscreen-printed electrodes as described above require soaking orhydration to ensure stable measurement of the potential differencebetween the electrodes, i.e., the voltage between the working and thereference electrodes. Manual cleaning or hydration (lavage) of thesensors would not work because the therapeutic cavity would not beconveniently accessible as it would require the removal of the dressingto provide sufficient access to the tissue interface 108. Thus, theability to provide cleansing and/or therapeutic solutions directly tothe therapy cavity 403 for cleansing or hydration as described abovealong with the ability to deliver negative pressure and otherpH-modulating controlled instillates such as phosphate buffered salineor weak acidic acids is a distinct advantage to enhance operation of thesystems and methods described herein.

As described above in more detail, some embodiments of the therapysystem 100 may include a solution source, such as solution source 114,without an instillation pump, such as the instillation pump 116.Instead, the solution source 114 may be fluidly coupled directly orindirectly to the dressing interface 400, and may further include theinstillation regulator 115 electrically coupled to the controller 110 asdescribed above. In operation, the negative pressure source 104 mayapply negative pressure to the therapy cavity 403 through the container112 and the negative pressure lumen 430 to create a vacuum within thespace formed by the therapy cavity 403 and the tissue interface 108. Thevacuum within the space would draw cleansing and/or hydration fluid fromthe solution source 114 and through the instillation lumen 433 into thespace for cleansing or wetting the sensors and/or the tissue interface108. In some embodiments, the controller 110 may be programmed tomodulate the instillation regulator 115 to control the flow of suchfluids into the space. Any of the embodiments described above may beutilized to periodically clean, rinse, or hydrate the sensors, thetissue interface, and the tissue site using saline along with otherpH-modulating instillation fluids such as weak acidic acids.

Referring now to FIGS. 10A and 10B, a second dressing is showncomprising a dressing interface 500 that may be substantially similar tothe first dressing interface 400 as indicated in part by the last twodigits of the reference numerals identifying various components of thesecond dressing interface 500 as antecedent basis if not describeddifferently below. The second dressing interface 500 may be a lowerprofile embodiment of the first dressing interface 400 because thesecond dressing interface 500 does not include a neck portion similar tothe neck 407 that angles upwardly away from the tissue site 410.Eliminating the neck portion allows the conduit 405 to be coupled to thesecond dressing interface 500 parallel to the tissue site 410.Otherwise, like the first dressing interface 400, the dressing interface500 may comprise a housing 501 and a wall 502 disposed within thehousing 501 wherein the wall 502 forms a therapy cavity 503 that opensto the manifold 408 when disposed at the tissue site 410 and a componentcavity 504 opening away from the tissue site 410 of the upper portion ofthe dressing interface 500. In some embodiments, sensing portions ofvarious sensors may be disposed within the therapy cavity 503, andelectrical devices associated with the sensors may be disposed withinthe component cavity 504 and electrically coupled to the sensingportions through the wall 502. Electrical devices disposed within thecomponent cavity 504 may include components associated with some exampleembodiments of the therapy system of FIG. 1 as described above. Thedressing interface 500 further comprises the sensor assembly 525including all of the sensors and the associated electrical devices thathave been described in more detail above with respect to the firstdressing interface 400 as indicated by the reference numerals.

In some embodiments, the second dressing interface 500 may differfurther from the first dressing interface 400. For example, the housing501 may comprise several pieces including a housing body 570 havingwalls that may have a generally cylindrical shape including a proximalwall section 571 and a distal wall section 572. The proximal wallsection 571 may comprise a proximal bracket 573 and the distal wallsection 572 may comprise a distal bracket 574 that support the sensorassembly 525. The second dressing interface 500 may differ further fromthe first dressing interface 400 because it may comprise two separateports to accommodate two separate conduits, conduit 505 and conduit 555,rather than a single conduit 405 that includes a primary and auxiliarylumens. In some embodiments, the conduit 505 may include a negativepressure lumen 530 fluidly coupled to the negative pressure source 104through the container 112 for delivering negative pressure to thetherapy cavity 503 as indicated by arrow 531. In some embodiments, theconduit 555 may include and an instillation lumen 533 fluidly coupled tothe instillation source 114 for delivery of cleansing and/orinstillation fluids as indicated by arrow 534. The proximal wall section571 may further comprise a negative-pressure port 576 configured to befluidly coupled to the negative pressure lumen 530 of the conduit 505,and a port 577 configured to be fluidly coupled to the instillationlumen 533 of the conduit 555.

In some embodiments, the housing 501 may further comprise a flangeportion such as, for example, a flange 509, that is the terminus of thehousing 501 adapted to contact and provide a seal over the manifold 408thereby forming the therapy cavity 503. Because the housing 501 maycomprise several pieces, each piece of the housing 501 may furthercomprise a portion of the flange 509 in some example embodiments. Thesecond dressing may further comprise a drape ring 513 covering thecircumference of the flange 509 and the adjacent portion of the drape406 to better seal the therapy cavity 503 of the housing 501 over themanifold 408 and the tissue site 410.

The second dressing interface 500 may differ further from the firstdressing interface 400 because the housing 501 may further compriseshaped features or baffles disposed within the therapy cavity 503 andoperatively disposed adjacent the port 576 and the port 577 to directthe flow of the instillation fluids on fluid delivery and removalpathways to adequately clean and/or hydrate the sensors as described inmore detail above. In some embodiments, the housing 501 may furthercomprise directional baffles 581 and 583 extending from the wall of theproximal wall section 571 towards the distal wall section 572 on eitherside of the of the ports to direct the flow of fluids along the fluiddelivery and removal pathways under both vacuum and instillationconditions such that the sensors are exposed to the flow of fluids. Insome embodiments, the housing 501 may further comprise a separationbaffle 582 extending from the wall of the proximal wall section 571towards the distal wall section 572 and between the of the ports toseparate the initial delivery of fluid adjacent the port 577 from thefinal removal of fluid adjacent the port 576 so that the flow of fluidreaches the sensors rather than being prematurely drained form thetherapy cavity 503. For example, this embodiment is effective toadequately hydrate the pH sensor 520 to ensure that the pH sensor 520 isalways exposed to the flow of fluids and that the pH sensor 520 can bepre-soaked to immediately measure the acidity of fluids from the tissuesite.

Referring now to FIGS. 11A and 11B, another example embodiment of thedressing interface 500 is shown that differs from the embodiment shownin FIGS. 10A and 10B because the dressing interface 500 comprises athird port to accommodate a conduit having a venting lumen that may befluidly coupled to the vent regulator 118 for purging fluids from thetherapy cavity 403. In some embodiments, the conduit may be separatefrom the conduit 505 and the conduit 555 and fluidly coupled to thethird port. In other embodiments, the conduit may be configured in aside-by-side configuration with either one, or both, of the other twoconduits. In yet other embodiments, the conduit may be configured withtwo lumens that include the venting lumen and either one, or both, ofthe other two lumens. For example, a conduit 655 has a venting lumen 633and is configured in a side-by-side configuration with negative pressureconduit 505. The venting lumen 633 may be fluidly coupled to a thirdport 678 that extends through the proximal wall section 571. In someembodiments, the third port 678 may extend through the baffle 581 sothat the third port 678 opens closer to the distal wall section 572 toenhance the removal of fluids from the therapy cavity 503 as describedin more detail above. In some embodiments, the port 678 may comprise aseparate conduit extending from the proximal wall section 571 toward thewall of the distal wall section 572. In operation, the venting lumen 633is similar to the vent conduit 145 that may be fluidly coupled to thevent regulator 118 for purging fluids from the therapy cavity 503 asindicated by arrow 636. The instillation lumen 533 may be fluidlycoupled to the instillation source 114 for delivery of cleansing and/orinstillation fluids to the therapy cavity 503 as indicated by arrow 534.The port 577 may be configured to be fluidly coupled to the instillationlumen 533 of the conduit 555. The instillation lumen 533 is similar tothe instillation conduit 133 that may be fluidly coupled directly orindirectly to the solution source 114 for flushing and removing fluidsfrom the therapy cavity 403 by simultaneously applying negative pressurethrough the negative pressure lumen 530.

Referring back to FIGS. 10A and 10B, the component cavity 504 containingthe electrical devices in some embodiments may be open to the ambientenvironment such that the electrical devices are exposed to the ambientenvironment. The component cavity 504 of the dressing interface 500unlike the dressing interface 400 may already be closed by as integralportion of the housing body 570 and, as such, may not require a coversuch as, for example, the cap 411 to protect the electrical devices. Insome other embodiments, the upper portion of the housing body 570 maycomprise an opening for access to the electrical devices, wherein theopening is covered by a cover 511 to close the component cavity 504. Insome example embodiments, the component cavity 504 may still be ventedto the ambient environment to provide cooling and access to theelectrical devices if needed. In some other example embodiments, thecomponent cavity 504 may be vented to the ambient environment to providea source of ambient pressure and/or humidity for the pressure sensor 516and/or the humidity sensor 518 for comparison to the pressure andhumidity within the therapy cavity 503 as described above.

More specifically, the pressure sensor 516, the temperature and humiditysensor 518, and the pH sensor 520 may be disposed in the housing 501with each one having a sensing portion disposed in the therapy cavity503 of the housing 501 and associated electronics or outputs extendinginto the component cavity 504. In some example embodiments, the sensorsmay be coupled to or mounted on the wall 502 and electrically coupled toelectrical components and circuits such as, for example, amicroprocessor disposed within the component cavity 504 by electricalconductors extending through the wall 502. In some preferredembodiments, the electrical conductors extend through pathways in thewall 502 while keeping the therapy cavity 503 electrically andpneumatically isolated from the component cavity 504. In this exampleembodiment, the circuit board 532 may be the wall 502 that separates thetherapy cavity 503 from the component cavity 504. In some otherembodiments, the wall 502 may comprise a sintered polymer that is highlyhydrophobic and molded within the housing 501. Essentially, thepolymeric wall 502 would effectively function as a large filter tohermetically isolate the component cavity 504 from the therapy cavity503 and the wound fluids being drawn in through the manifold 408.

In some embodiments, the electrical circuits and/or componentsassociated with the sensors that are mounted on the circuit board 532within the component cavity 504 may be electrically coupled to thecontroller 110 to interface with the rest of the therapy system 100 asdescribed above. In some embodiments, the communications module 522 maybe disposed in the component cavity 504 of the housing 501 and mountedon the circuit board 532 within the component cavity 504. For example,the electrical circuits and/or components associated with the sensorsalong with the terminal portion of the sensors may be electricallycoupled to the controller 110 by wireless means such as an integrateddevice implementing Bluetooth® Low Energy wireless technology.

In some embodiments, the power source 524 may be disposed within thecomponent cavity 504 of the housing 501, mounted on the circuit board532, and secured in place to the circuit board 532 by a bracket 526. Thepower source 524 may be, for example, a battery that provides a 3-voltsource for the communications module 522 and the other electroniccomponents within the component cavity 504 associated with the sensors.In some example embodiments, the sensors, the electrical circuits and/orcomponents associated with the sensors, the wall 502 and/or the circuitboard 532, the communications module 522, and the power source 524 maybe integrated as components of the sensor assembly 525. In somepreferred embodiments, the wall 502 of the sensor assembly 525 may bethe circuit board 532 as described above that provides a seal betweentissue site 410 and the atmosphere when positioned over the openingbetween the therapy cavity 503 and the component cavity 504 of thehousing 501.

Each of the sensors may comprise a sensing portion extending into thetherapy cavity 503 of the housing 501 and a terminal portionelectrically coupled to the electrical circuits and/or components withinthe component cavity 504. The pressure sensor 516 may be disposed on thecircuit board 532 within the therapy cavity 503 of the sensor assembly525 that provides a seal between tissue site 410 and the atmosphere asdescribed above. In some embodiments, the pressure sensor 516 may be adifferential gauge comprising a sensing portion 542 and a terminalportion or vent 543. The vent 543 of the pressure sensor 516 may befluidly coupled through the circuit board 532 to the component cavity504 and the ambient environment by a vent hole 544 extending through thecircuit board 532. The sensing portion 542 of the pressure sensor 516may be positioned in close proximity to the manifold 408 to optimizefluid coupling and accurately measure the wound pressure (WP) at thetissue site 410.

In some embodiments, the humidity sensor 518 may comprise a temperaturesensor for measuring the temperature at the tissue site 410. Thehumidity sensor 518 may also be supported on the circuit board 532 ofthe sensor assembly 525. In some embodiments, the humidity sensor 518may comprise a sensing portion that is electrically coupled through thecircuit board 532 to a microprocessor disposed within the componentcavity 504. The sensing portion of the humidity sensor 518 may bedisposed within the therapy cavity 503 that includes a fluid pathway 545extending from the port 577 to the port 576 represented by a series ofdashed arrows and further represented by the arrow 534 and the arrow531, respectively, to sense both the humidity and the temperature. Thesensing portion of the humidity sensor 518 may be positioned within thefluid pathway 545 to limit direct contact with bodily fluids being drawninto the negative pressure lumen 530 from the tissue site 410 and toenhance exposure to the cleansing fluids from the instillation lumen533.

In some embodiments, the humidity sensor 518 also may comprise a secondhumidity sensor (not shown) that may be fluidly coupled to the componentcavity 504 through a vent hole 541 extending through the circuit board532 to sense the ambient environment within the component cavity 504.Alternatively, the sensor assembly 525 may further comprise a secondhumidity sensor 519 having a sensing portion disposed within thecomponent cavity 504 on the wall 502 and electrically coupled toelectrical components and circuits such as, for example, amicroprocessor also disposed within the component cavity 504. The secondhumidity sensor 519 also may comprise a temperature sensor component.Thus, the second humidity sensor 519 may be configured to sense therelative humidity of the ambient environment within the component cavity504 for comparison to the relative humidity of the therapeuticenvironment within the therapy cavity 503 sensed by the humidity sensor518. Sensing a differential humidity from such comparisons may offer anumber of advantages such as, for example, enhanced leak detection thatdistinguishes the type of leak occurring, full dressing determinations(automated fill assist), and enhanced the blockage detection, all ofsuch advantages disclosed in Provisional Application No. 62/617,517filed Jan. 15, 2018, which is incorporated herein by reference.

The pH sensor 520 also may comprise a sensing portion disposed withinthe therapy cavity 503 that is electrically coupled through the circuitboard 532 to an analog front end device mounted on the other side of thecircuit board 532 within the component cavity 504. The analog front enddevice measures minute voltage potential changes provided by the sensingportion. The sensing portion of the pH sensor 520 may be fluidly coupledto the space within the therapy cavity 503 by being positioned in thefluid pathway 545 that extends into the negative pressure lumen 530 asdescribed above. The sensing portion of the pH sensor 520 may be formedand positioned within the fluid pathway 545 so that the sensing portiondirectly contacts the wound fluid without contacting the wound itself sothat the sensing portion of the pH sensor 520 does not interfere withthe wound healing process. In some embodiments, the pH sensor 520 maybe, for example, the pH sensor 450 shown in FIG. 9A that comprises apair of printed medical electrodes including a working electrode 451 anda reference electrode 452 as more fully described above. In some otherembodiments, the pH sensor 520 may include a third electrode such as,for example, the pH sensor 460 shown in FIG. 9B that comprises a thirdelectrode or a counter electrode 462 in addition to the workingelectrode 451 and the reference electrode 452 of the pH sensor 450 asmore fully described above. The sensing portion of the pH sensor 520also may be positioned within the fluid pathway 545 to enhance exposureto the fluids from the instillation lumen 533 for the necessarycleansing and hydration. In the embodiments described above, the sensingportion of the pH sensors 420 and 520 when used with the combination ofnegative pressure and instillation, relies on using the vacuum inducedflow created in the therapeutic cavities 403 and 503 to expose thesensing portion to wound fluids for measurement when wound fluids arebeing removed from the cavity and then using the instillation ofcleansing fluids to clean and hydrate the sensing portion in order torecalibrate the pH sensors during routine instillation therapyprocedures. The pH sensors may also be used along with other sensors todetermine the type of fluid being instilled into the therapy cavity toprevent incorrect fluids from being delivered to, or left within, thetherapy cavity, and then transmit a signal to the controller 110 thatshuts down or overrides the delivery system upon detection. For example,the pH sensor may detect fluids that do not correspond to the correct pHvalue and upon detection overrides the delivery system.

In some embodiments where the component cavity 504 is covered or sealed,the component cavity 504 may be vented to the ambient environment toprovide cooling and access to the electrical devices if needed. Thecomponent cavity 504 may also be vented to the ambient environment inorder to provide a source of ambient pressure for the pressure sensor516 and a source of ambient humidity for the second humidity sensor 519that can be used for comparison to the pressure and relative humiditywithin the therapy cavity 503 as described above. In such embodiments,access to the ambient environment may be provided by venting the upperportion of the dressing interface 500 itself. However, the dressinginterface 500 is fixed to the manifold 408 at the tissue site, so it ispossible that the user or caregiver may inadvertently block venting tothe component cavity 504 while adjusting the drape such as, for example,the cover 106. Additionally, the user or patient may inadvertently sitor lay on the dressing interface 500 that may also block venting to thecomponent cavity 504. In both cases, blocking access to the ambientenvironment could cause the electrical devices to overheat resulting inerroneous reading communications within the system or cause the sensorsto provide erroneous readings detrimental to the patient. Therefore, insome embodiments it may be desirable to modify the component cavity 504by sealing the component cavity 504 to form an ambient chamber withinthe dressing interface 500 and providing a port coupled to the ambientchamber that may be coupled to an ambient conduit extending to alocation sufficiently distant from the dressing interface 500 and thetissue site to avoid such mishaps. Such embodiments provide remoteaccess to the ambient environment that may enhance the performance andsafety of the dressing interface 500 by providing more consistentreadings and data for promoting healing at the tissue site.

Referring again to FIGS. 11A and 11B, another example embodiment of thedressing interface 500 is shown that differs from the embodiment shownin FIGS. 10A and 10B to the extent that the component cavity 504 issealed to form an ambient chamber 604 and further comprises an ambientport 578 that may be fluidly coupled to an ambient conduit 585. In someembodiments, the ambient conduit 585 may comprise an ambient lumen 590fluidly coupled to the ambient chamber 604 for providing remote accessto the ambient environment as indicated by the arrow 591. In someembodiments, the ambient conduit 585 may be separate from the conduit505 and fluidly coupled to the ambient port 578. In other embodiments,the ambient conduit 585 may be configured in a side-by-sideconfiguration with the conduit 505 to form a single conduit. In someembodiments, the other end of the ambient conduit 585 may be coupled tothe ambient environment by an in-line connector that fluidly couples thedressing interface 500 to the container 112 as shown in FIG. 1 toprovide a source of air from the ambient environment to the ambientchamber 604. In some embodiments, the in-line connector may provide airfrom the ambient environment that provides an accurate indication of theambient pressure and humidity provided by the pressure sensor 516 andthe second humidity sensor 519 for comparison to the pressure andhumidity within the therapy cavity 503 provided by the pressure sensor516 and the humidity sensor 518, respectively, that are fluidly coupledto the therapy cavity 503.

Referring to FIG. 12 , a schematic diagram of fluid conduits couplingthe dressing interface 500 to the container 112 including an in-lineconnector 690 is shown, and in some embodiments may be associated withsome embodiments of the dressing interfaces shown in FIGS. 1, 4, 10A and11A for providing negative pressure and/or instillation therapy. In someembodiments, the in-line connector 690 may comprise two connector partsthat mate together including a first connector part 691 and a secondconnector part 692. In some example embodiments, the first connectorpart 691 may be fluidly coupled to the negative pressure conduit 135coupled to the container 112 and/or the venting conduit 145 coupled tothe regulator 118. In some example embodiments, the second connectorpart 692 may be fluidly coupled to the negative pressure conduit 505and/or the vent conduit 655 which are fluidly coupled to theircorresponding conduits, i.e., the negative pressure conduit 135 and theventing conduit 145, respectively, when the two parts are connected toeach other.

In some example embodiments, the second connector part 692 also may havean internal chamber including an orifice or port 693 open to the ambientenvironment that may be fluidly coupled to the ambient lumen 590 of theambient conduit 585 which in some embodiments may terminate at theinternal chamber within the second connector part 692. The orifice orport 693 may be located at the side of the second connector part 692 tominimize the possibility that the orifice may be covered or occludedinadvertently as a result of the patient or user laying on the in-lineconnector 690. In some embodiments, the second connector part 692 mayfurther comprise a filter 694 that covers the orifice or port 693prevent fluid ingress into the ambient lumen 590. Because the ambientchamber 604 is sealed and not in fluid communication with the therapycavity 503, the filter 694 would not necessarily need to be a bacterialfilter for protecting the ambient lumen 590 from contamination bybacteria or other particles. Thus, the ambient conduit 585 and the port693 provide the ambient chamber 604 with access to the ambientenvironment at a location removed from the dressing interface 500 tohelp prevent the loss of access to the ambient environment.

In some alternative example embodiments not shown in FIG. 12 , the otherend of the ambient conduit 585 may be coupled to the ambient environmentby the in-line connector 690 and another ambient conduit 185 thatterminates proximate the container 112 to provide the ambient chamber604 with access to the ambient environment from a location even furtherremoved from the dressing interface 500 and the in-line connector 690.In some embodiments, the ambient conduit 185 rather than the secondconnector part 692 may comprise an orifice (not shown) proximate thecontainer 112 that provides access to the ambient environment, and alsomay be covered by a filter to prevent fluid ingress as described above.The second connector part 692 may be fluidly coupled in a similarfashion to the embodiment shown in FIG. 12 wherein the negative pressureconduit 505 and/or the vent conduit 655 are fluidly coupled to theircorresponding conduits, i.e., the negative pressure conduit 135 and theventing conduit 145, respectively, when the two parts are connected toeach other. Providing access to the ambient environment from a locationof the ambient conduit 185 proximate the container 112 may furtherreduce the possibility that the orifice might be covered or occluded bythe patient or caregiver. For example, it will be less likely that apatient might inadvertently roll over a container or the device to whichit is attached because the container and/or the device is normallylarger than an in-line connector.

In some embodiments, the negative pressure conduit 505, the ambientconduit 585 and the vent conduit 655 may be structured as separateconduits as shown in FIG. 12 . In some other embodiments, the negativepressure conduit 505, the ambient conduit 585 and the vent conduit 655may be bundled into other multiple or single embodiments such as, forexample, a connector conduit 695 that includes the functionality of allthree conduits. Referring more specifically to FIG. 13A, the connectorconduit 695 is a single conduit comprising three separate lumensincluding the negative pressure lumen 530, the ambient lumen 590, andthe vent lumen 633, that may be substituted for the three separateconduits. Referring to FIG. 13B, the connector conduit 695 may bemodified as conduit 697 to further comprise the instillation lumen 533rather than having a separate instillation conduit such as, for example,the instillation conduit 555 as shown in FIG. 10B.

In operation, the tissue interface 108 may be placed within, over, on,or otherwise proximate a tissue site, such as tissue site 150 as shownin FIG. 4 . The cover 106 may be placed over the tissue interface 108and sealed to an attachment surface near the tissue site 150. Forexample, the cover 106 may be sealed to undamaged epidermis peripheralto a tissue site. Thus, the dressing 102 can provide a sealedtherapeutic environment proximate to a tissue site, substantiallyisolated from the external environment, and the negative-pressure source104 can reduce the pressure in the sealed therapeutic environment.

Some embodiments of therapy systems including, for example, the therapysystem 100 including the dressing interface 400 and the dressinginterface 500, are illustrative of a method for applying fluids to atissue interface and sensing a property of a fluid at a tissue site fortreating the tissue site. For example, the method may comprisepositioning a dressing interface on the tissue site, the dressinginterface having a housing having a body including a therapy cavity anda component chamber fluidly isolated from the therapy cavity, thetherapy cavity having an opening configured to be in fluid communicationwith the tissue interface, and a control device disposed within thecomponent chamber. The method may further comprise providing thecomponent chamber with access to the ambient environment through anambient port to a sensor disposed within the therapy cavity and coupledto the control device. The method also comprises applying negativepressure to the therapy cavity through a negative-pressure port to drawfluids from the tissue interface and into the therapy cavity. The methodmay also comprise sensing the property of the fluid within the therapycavity with the sensor, and then providing a property signal to thecontrol device indicative of the property of the fluid relative to thecorresponding property of the ambient environment.

Some other embodiments of therapy systems including, for example, thetherapy system 100 including the dressing interface 400 and the dressinginterface 500, are illustrative of a method for providingreduced-pressure to a tissue interface and sensing properties of fluidsextracted from a tissue site for treating the tissue. In one exampleembodiment, the method may comprise positioning a housing of a dressinginterface having an aperture in fluid communication with the tissueinterface disposed adjacent the tissue site. The dressing interface maycomprise a wall disposed within the housing to form a therapy cavitywithin the housing and a component cavity fluidly sealed from thetherapy cavity, wherein the therapy cavity opens to the aperture. Suchdressing interface may further comprise a reduced-pressure port fluidlycoupled to the therapy cavity and adapted to be fluidly coupled to areduced-pressure source, and a control device disposed in the componentcavity. The dressing interface may further comprise a pH sensor, atemperature sensor, a humidity sensor, and a pressure sensor, eachhaving a sensing portion disposed within the therapy cavity and eachelectrically coupled to the control device through the wall. The methodmay further comprise applying reduced pressure to the therapy cavity todraw fluids from the tissue interface into the therapy cavity and out ofthe reduced-pressure port. The method may further comprise sensing thepH, temperature, humidity, and pressure properties of the fluids flowingthrough therapy cavity utilizing the sensing portion of the sensors andoutputting signals from the sensors to the control device. The methodmay further comprise providing fluid data from the control deviceindicative of such properties, and inputting the fluid data from thecontrol device to the therapy system for processing the fluid data andtreating the tissue site in response to the fluid data.

The systems, apparatuses, and methods described herein may provide othersignificant advantages over dressing interfaces currently available. Forexample, a patient may require two dressing interfaces for two tissuesites, but wish to use only a single therapy device to provide negativepressure to and collect fluids from the multiple dressing interfaces tominimize the cost of therapy. In some therapy systems currentlyavailable, the two dressing interfaces would be fluidly coupled to thesingle therapy device by a Y-connector. The problem with thisarrangement is that the Y-connector embodiment would not permit thepressure sensor in the therapy device to measure the wound pressure inboth dressing interfaces independently from one another. A significantadvantage of using a dressing interface including in situ sensors, e.g.,the dressing interface 400 including the sensor assembly 425 and thepressure sensor 416, is that multiple dressings may be fluidly coupledto the therapy unit of a therapy system and independently providepressure data to the therapy unit regarding the associated dressinginterface. Each dressing interface 400 that is fluidly coupled to thetherapy unit for providing negative pressure to the tissue interface 108and collecting fluids from the tissue interface 108 has the additionaladvantage of being able to collect and monitor other information at thetissue site, as well as the humidity data, temperature data, and the pHdata being provided by the in situ sensors the sensor assembly 425. Forexample, the sensor assembly 425 may include accelerometers to determinethe patient's compliance with specific therapy treatments includingvarious exercise routines and/or various immobilization requirements.

Another advantage of using the dressing interface 400 that includes apressure sensor in situ such as, for example, the pressure sensor 416,is that the pressure sensor 416 can more accurately monitor the woundpressure (WP) at the tissue site and identify blockages and fluid leaksthat may occur within the therapeutic space as described in more detailabove. Another advantage of using a dressing interface including in situsensors, e.g., the dressing interface 400, is that the sensor assembly425 provides additional data including pressure, temperature, humidity,and pH of the fluids being drawn from the tissue site that facilitatesimproved control algorithms and wound profiling to further assist thecaregiver with additional information provided by the therapy unit ofthe therapy system to optimize the wound therapy being provided and theoverall healing progression of the tissue site when combined withappropriate control logic.

The disposable elements can be combined with the mechanical elements ina variety of different ways to provide therapy. For example, in someembodiments, the disposable and mechanical systems can be combinedinline, externally mounted, or internally mounted. In another example,the dressing interface 400 may be a disposable element that is fluidlycoupled to a therapy unit of a therapy system as described in moredetail above.

While shown in a few illustrative embodiments, a person having ordinaryskill in the art will recognize that the systems, apparatuses, andmethods described herein are susceptible to various changes andmodifications. For example, certain features, elements, or aspectsdescribed in the context of one example embodiment may be omitted,substituted, or combined with features, elements, and aspects of otherexample embodiments. Moreover, descriptions of various alternativesusing terms such as “or” do not require mutual exclusivity unlessclearly required by the context, and the indefinite articles “a” or “an”do not limit the subject to a single instance unless clearly required bythe context. Components may be also be combined or eliminated in variousconfigurations for purposes of sale, manufacture, assembly, or use. Forexample, in some configurations the dressing 102, the container 112, orboth may be eliminated or separated from other components formanufacture or sale. In other example configurations, the controller 110may also be manufactured, configured, assembled, or sold independentlyof other components.

The appended claims set forth novel and inventive aspects of the subjectmatter described above, but the claims may also encompass additionalsubject matter not specifically recited in detail. For example, certainfeatures, elements, or aspects may be omitted from the claims if notnecessary to distinguish the novel and inventive features from what isalready known to a person having ordinary skill in the art. Features,elements, and aspects described herein may also be combined or replacedby alternative features serving the same, equivalent, or similar purposewithout departing from the scope of the invention defined by theappended claims.

What is claimed is:
 1. A dressing interface for connecting a source offluids to a tissue interface and sensing properties of fluid at a tissuesite, the dressing interface comprising: a housing having a bodyincluding a therapy cavity and a component cavity fluidly isolated fromthe therapy cavity, the therapy cavity having an opening configured tobe in fluid communication with the tissue interface; a negative-pressureport fluidly coupled to the therapy cavity and adapted to be fluidlycoupled to a negative-pressure source; an ambient port fluidly coupledto the component cavity and adapted to be fluidly coupled to an ambientenvironment; a controller disposed within the component cavity andincluding a microprocessor; at least one sensor electrically coupled tothe microprocessor and having a sensing portion disposed within thetherapy cavity and a vent portion fluidly coupled to the componentcavity through a vent hole; and a fluid conduit having a first endcoupled to the ambient port and a second end.
 2. The dressing interfaceof claim 1, further comprising a pH sensor having a sensing portiondisposed within the therapy cavity and electrically coupled to themicroprocessor.
 3. The dressing interface of claim 2, further comprisingan instillation port fluidly coupled to the therapy cavity and adaptedto fluidly couple an instillation source to the tissue interface.
 4. Thedressing interface of claim 3, wherein the sensing portion of the pHsensor is disposed proximate the instillation port.
 5. The dressinginterface of claim 1, wherein the at least one sensor comprises at leastone of a temperature sensor and a humidity sensor.
 6. The dressinginterface of claim 5, further comprising an instillation port fluidlycoupled to the therapy cavity and adapted to fluidly couple aninstillation source to the tissue interface.
 7. The dressing interfaceof claim 1, wherein the control device further comprises a wirelesstransmitter coupled to the microprocessor.
 8. The dressing interface ofclaim 1, further comprising a fluid connector having a connector portfluidly coupled to the second end of the fluid conduit and the ambientenvironment through an orifice in the fluid connector.
 9. The dressinginterface of claim 8, wherein the fluid connector further comprises afilter disposed between the connector port and the ambient environment.10. The dressing interface of claim 1, wherein the second end isconfigured to terminate proximate a canister fluidly coupled to thetherapy cavity and having an orifice configured to access the ambientenvironment.
 11. The dressing interface of claim 1, wherein the secondend configured to terminate within a canister fluidly coupled to thetherapy cavity and having an orifice covered by a filter and configuredto access the ambient environment.
 12. The dressing interface of claim1, further comprising a fluid conductor having a first end coupled tothe negative-pressure port and the ambient port.
 13. The dressinginterface of claim 1, further comprising a vent port configured to befluidly coupled to a vent conduit fluidly coupled to the therapy cavityand adapted to enable airflow into the therapy cavity, and a fluidconductor having a first end coupled to the negative-pressure port, theambient port, and the vent port.
 14. The dressing interface of claim 13,further comprising a fluid connector having a connector oriface, whereinthe fluid conductor has a second end fluidly coupling the ambient portto the connector oriface for sensing properties of the ambientenvironment.
 15. A system for connecting a source of fluids to a tissueinterface and sensing properties of fluid at a tissue site, the systemcomprising: a dressing interface comprising: a housing having a bodyincluding a therapy cavity and a component chamber fluidly isolated fromthe therapy cavity, the therapy cavity having an opening configured tobe in fluid communication with the tissue interface; a negative-pressureport fluidly coupled to the therapy cavity; an ambient port fluidlycoupled to the component chamber; a control device disposed within thecomponent chamber including a microprocessor and a transmitter coupledto the microprocessor; and at least one sensor having a sensing portiondisposed within the therapy cavity and coupled to the microprocessor,and further having an ambient input fluidly coupled to the componentchamber for sensing properties of an ambient environment; a canisteradapted to be fluidly coupled to a source of reduced pressure; and afluid conductor fluidly coupling the negative-pressure port to thecanister, and fluidly coupling the ambient port to the ambientenvironment.
 16. A method of applying negative-pressure to a tissueinterface and sensing a property of fluid at a tissue site, the methodcomprising: positioning a dressing interface on the tissue site, thedressing interface having a housing having a body including a therapycavity and a component chamber fluidly isolated from the therapy cavity,the therapy cavity having an opening configured to be in fluidcommunication with the tissue interface, and a control device disposedwithin the component chamber; providing the component chamber withaccess to an ambient environment through an ambient port to a sensordisposed within the therapy cavity and coupled to the control device;applying negative pressure to the therapy cavity through anegative-pressure port to draw fluids from the tissue interface and intothe therapy cavity; sensing the property of the fluid within the therapycavity with the sensor disposed within the therapy cavity; providing aproperty signal to the control device indicative of the property of thefluid relative to a corresponding property of the ambient environment;instilling fluids through an instillation port into the therapy cavityto cleanse the sensor and purging fluids from the therapy cavity; andsensing pH properties of the fluid within the therapy cavity providedfrom a pH sensor disposed within the therapy cavity and coupled to thecontrol device, wherein sensing pH properties of the fluid comprisessensing the pH properties of the fluids prior to providing instillationfluids to the therapy cavity.
 17. The method of claim 16, furthercomprising sensing the pH properties of the fluids after providinginstillation fluids to the therapy cavity.